Tag Archives: Nuclear Experiment

A new $^{12}$C + $^{12}$C nuclear reaction rate: impact on stellar evolution [SSA]

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http://arxiv.org/abs/2111.15224


This work presents new $^{12}$C + $^{12}$C reaction rates in the form of numerical tables with associated uncertainty estimation, as well as analytical formulae that can be directly implemented into stellar evolution codes. This article further describes the impact of these new rates on C-burning in stars. We determine reaction rates for two cross-section extrapolation models: one based on the fusion-hindrance phenomenon, and the other on fusion-hindrance plus a resonance, and compare our results to previous data. Using the GENEC stellar evolution code, we study how these new rates impact the C-burning phases in two sets of stellar models for stars with 12 M${\odot}$ and 25 M${\odot}$ initial masses chosen to be highly representative of the diversity of massive stars. The effective temperatures of C-burning in both sets of stellar models are entirely covered by the sensitivity of the present experimental data, and no extrapolation of the rates is required. Although, the rates may differ by more than an order of magnitude for temperatures typical of C-burning, the impacts on the stellar structures during that phase remain modest. This is a consequence of the readjustment of the stellar structure to a change of nuclear reaction rate for reactions important for energy production. For the hindrance case, the C-burning phase is found to occur at central temperatures 10\% higher than with the hindrance plus resonance rate. Its C-burning lifetime is reduced by a factor of two. This model, nevertheless, loses more entropy than the other one thus enters earlier into the degeneracy regime which will impact the last stages of the evolution at the pre-core collapse time. The hindrance model produces up to 60% more neon. The impact of the different rates on the s-process occurring during the C-burning phase is modest, changing final abundances of s-processed elements by at most 20% (cobalt).

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E. Monpribat, S. Martinet, S. Courtin, et. al.
Wed, 1 Dec 21
83/110

Comments: 13 pages, 9 figures

Mass measurements of $^{60-63}$Ga reduce X-ray burst model uncertainties and extend the evaluated $\mathbf{T=1}$ isobaric multiplet mass equation [CL]

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http://arxiv.org/abs/2111.12788


We report precision mass measurements of neutron-deficient gallium isotopes approaching the proton drip line. The measurements of $^{60-63}$Ga performed with TITAN’s multiple-reflection time-of-flight mass spectrometer provide a more than threefold improvement over the current literature mass uncertainty of $^{61}$Ga and mark the first direct mass measurement of $^{60}$Ga. The improved precision of the $^{61}$Ga mass has important implications for the astrophysical rp-process, as it constrains essential reaction Q-values near the $^{60}$Zn waiting point. Based on calculations with a one-zone model, we demonstrate the impact of the improved mass data on prediction uncertainties of X-ray burst models. The first-time measurement of the $^{60}$Ga ground-state mass establishes the proton-bound nature of this nuclide; thus, constraining the location of the proton drip line along this isotopic chain. Including the measured mass of $^{60}$Ga enables us to extend the evaluated $T=1$ isobaric multiplet mass equation up to $A=60$.

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S. Paul, J. Bergmann, J. Cardona, et. al.
Mon, 29 Nov 21
26/94

Comments: 20 pages, 6 figures. Accepted for publication in Physical Review C

A Compact High-Resolution Muon Spectrometer Using Multi-Layer Gas Cherenkov Radiators [CL]

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http://arxiv.org/abs/2111.12512


In both particle physics and cosmic ray muon applications, a high-resolution muon momentum measurement capability plays a significant role not only in providing valuable information on the properties of subatomic particles but also in improving the utilizability of muons. Currently, muon momentum is estimated by reconstructing the muon path using a strong magnetic field and muon trackers. Alternatively, time-of-flight or multiple Coulomb scattering techniques are less frequently applied, especially when there is a need to avoid using a magnetic field. However, the measurement resolution is much lower than that of magnetic spectrometers, approximately 20% in the muon momentum range of 0.5 to 4.5 GeV/c whereas it is nearly 10% or less when using magnets and trackers. Here, we propose a different paradigm to estimate muon momentum that utilizes multi-layer pressurized gas Cherenkov radiators. Using the fact that the gas refractive index varies with pressure and temperature, we can optimize the muon Cherenkov threshold momentum for which a muon signal will be detected. By analyzing the optical signals from Cherenkov radiation, we show that the actual muon momentum can be estimated with a minimum resolution of +-0.05 GeV/c for a large number of radiators over the range of 0.1 to 10.0 GeV/c. The results also show that our spectrometer correctly classifies the muon momentum (~87% classification rate) in the momentum range of 0.1 to 10.0 GeV/c. We anticipate our new spectrometer will to provide an alternative substitute for the bulky magnets without degrading measurement resolution. Furthermore, we expect it will significantly improve the quality of imaging or reduce the scanning time in cosmic muon applications by being incorporated with existing instruments.

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J. Bae and S. Chatzidakis
Thu, 25 Nov 21
35/60

Comments: N/A

A Compact High-Resolution Muon Spectrometer Using Multi-Layer Gas Cherenkov Radiators [CL]

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http://arxiv.org/abs/2111.12512


In both particle physics and cosmic ray muon applications, a high-resolution muon momentum measurement capability plays a significant role not only in providing valuable information on the properties of subatomic particles but also in improving the utilizability of muons. Currently, muon momentum is estimated by reconstructing the muon path using a strong magnetic field and muon trackers. Alternatively, time-of-flight or multiple Coulomb scattering techniques are less frequently applied, especially when there is a need to avoid using a magnetic field. However, the measurement resolution is much lower than that of magnetic spectrometers, approximately 20% in the muon momentum range of 0.5 to 4.5 GeV/c whereas it is nearly 10% or less when using magnets and trackers. Here, we propose a different paradigm to estimate muon momentum that utilizes multi-layer pressurized gas Cherenkov radiators. Using the fact that the gas refractive index varies with pressure and temperature, we can optimize the muon Cherenkov threshold momentum for which a muon signal will be detected. By analyzing the optical signals from Cherenkov radiation, we show that the actual muon momentum can be estimated with a minimum resolution of +-0.05 GeV/c for a large number of radiators over the range of 0.1 to 10.0 GeV/c. The results also show that our spectrometer correctly classifies the muon momentum (~87% classification rate) in the momentum range of 0.1 to 10.0 GeV/c. We anticipate our new spectrometer will to provide an alternative substitute for the bulky magnets without degrading measurement resolution. Furthermore, we expect it will significantly improve the quality of imaging or reduce the scanning time in cosmic muon applications by being incorporated with existing instruments.

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J. Bae and S. Chatzidakis
Thu, 25 Nov 21
40/60

Comments: N/A

Dark Matter Search with the Nuclear Isomer Ta-180m [CL]

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http://arxiv.org/abs/2111.11497


There is compelling cosmological and astrophysical evidence of dark matter comprising 27% of the energy budget of the Universe. However, dark matter has never been observed in direct detection experiments. The long-time favorite model of Weakly Interacting Massive Particles saw a large experimental effort with steady progress over recent decades. Since also these large-scale searches remain unsuccessful to date, it is compelling to look at more exotic dark matter models which can be constrained with new approaches and much less scientific resources. Using nuclear isomers is one of these approaches. $^{180m}$Ta is the rarest known isotope with the longest-lived meta-stable state whose partial half-life limits are on the order of 10$^{14}$-10$^{16}$ yr. We investigate how strongly interacting dark matter and inelastic dark dark matter collides with $^{180m}$Ta, leading to its de-excitation. The energy stored in the meta-stable state is released in the transition, which becomes the signature for thermalized dark matter in a well-shielded underground experiment. We report on a direct detection experiment searching for these dark-matter-induced decay signatures which has further constrained the open parameter space. We also propose an indirect geochemical experiment to search for decay products of $^{180m}$Ta in tantalum minerals accumulated over 1 billion years.

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B. Lehnert
Wed, 24 Nov 21
54/61

Comments: N/A

Modulation of pulse profile as a signal for phase transitions in a pulsar core [HEAP]

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http://arxiv.org/abs/2111.10805


We calculate detailed modification of pulses from a pulsar arising from the effects of phase transition induced density fluctuations on the pulsar moment of inertia. We represent general statistical density fluctuations using a simple model where the initial moment of inertia tensor of the pulsar (taken to be diagonal here) is assumed to get random additional contributions for each of its component which are taken to be Gaussian distributed with certain width characterized by the strength of density fluctuations $\epsilon$. Using sample values of $\epsilon$, (and the pulsar deformation parameter $\eta$) we numerically calculate detailed pulse modifications by solving Euler’s equations for the rotational dynamics of the pulsar. We also give analytical estimates which can be used for arbitrary values of $\epsilon$ and $\eta$. We show that there are very specific patterns in the perturbed pulses which are observable in terms of modulations of pulses over large time periods. In view of the fact that density fluctuations fade away eventually leading to a uniform phase in the interior of pulsar, the off-diagonal components of MI tensor also vanish eventually. Thus, the modification of pulses due to induced wobbling (from the off-diagonal MI components) will also die away eventually. This allows one to distinguish these transient pulse modulations from the effects of any wobbling originally present. Further, the decay of these modulations in time directly relates to relaxation of density fluctuations in the pulsar giving valuable information about the nature of phase transition occurring inside the pulsar.

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P. Bagchi, B. Layek, A. Sarkar, et. al.
Tue, 23 Nov 21
66/84

Comments: 10 pages, 6 figures, submitted to MNRAS

COHERENT at the Spallation Neutron Source [CL]

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http://arxiv.org/abs/2111.07033


The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory provides an intense, high-quality source of neutrinos from pion decay at rest. This source was recently used for the first measurements of coherent elastic neutrino-nucleus scattering (CEvNS) by the COHERENT collaboration, resulting in new constraints of beyond-the-standard-model physics. The SNS neutrino source will enable further CEvNS measurements, exploration of inelastic neutrino-nucleus interactions of particular relevance for understanding of supernova neutrinos, and searches for accelerator-produced sub-GeV dark matter. Taking advantage of this unique facility, COHERENT’s suite of detectors in “Neutrino Alley” at the SNS is accumulating more data to address a broad physics program at the intersection of particle physics, nuclear physics, and astrophysics. This review describes COHERENT’s first two CEvNS measurements, their interpretation, and the potential of a future physics program at the SNS.

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P. Barbeau, Y. Efremenko and K. Scholberg
Tue, 16 Nov 21
81/97

Comments: 33 pages, 12 figures. Invited review for Annual Reviews of Nuclear and Particle Science

Status and Perspectives of Neutrino Physics [CL]

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http://arxiv.org/abs/2111.07586


This review demonstrates the unique role of the neutrino by discussing in detail the physics of and with neutrinos. We deal with neutrino sources, neutrino oscillations, absolute masses, interactions, the possible existence of sterile neutrinos, and theoretical implications. In addition, synergies of neutrino physics with other research fields are found, and requirements to continue successful neutrino physics in the future, in terms of technological developments and adequate infrastructures, are stressed.

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M. Athar, S. Barwick, T. Brunner, et. al.
Tue, 16 Nov 21
88/97

Comments: 227 pages; this review of the field of neutrino physics emerged from a report written by a panel on the request of IUPAP (International Union of Pure and Applied Physics). The mandate, the panel members and the report can be found on the web page of the panel at ht tps://www.iupapneutrinopanel.org

Density dependence of symmetry energy and neutron skin thickness revisited [CL]

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http://arxiv.org/abs/2111.05743


The correlation between neutron skin-thickness of a neutron-rich nucleus and slope parameter of symmetry energy is assessed as a function of density using relativistic mean field models containing non-linear couplings among different mesons. Models with larger skin were found to probe the slope parameter even at suprasaturation densities, whereas models with smaller skin were observed to be sensitive only at specific subsaturation density, connected to the average density of nuclei. Possible reasons behind this density dependence are explored systematically. These results might be model specific, which need to be reassessed in other type of interactions existing in the literature. Nevertheless, extrapolating the predictions at high densities from models, which are optimized by data at saturation or subsaturation densities, needs to be handled with care

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C. Mondal
Thu, 11 Nov 21
5/60

Comments: 6 figures, 6 pages

Can we decipher the composition of the core of a neutron star? [CL]

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http://arxiv.org/abs/2111.04520


Recent developments in the multi-messenger astronomy through gravitational waves (LIGO/Virgo) or X-ray timing data (NICER) have provided new constraints on the theories of nuclear physics, where an absolute energy density functional from ab-initio modelling is still not available. General relativity guarantees a unique one-to-one correspondence between static observables of neutron stars (NSs) such as mass-radius or tidal deformability and the equation of state (EoS) of beta equilibrated matter. However, these static properties are not enough to predict the composition of the interiors of NSs, even if one assumes that hadrons present in the neutron star core are only neutrons and protons. This statement is demonstrated through a simple analytical method based on a polynomial expansion of the EoS, and it is further reinforced by a full Bayesian analysis. We show that even additional empirical information on symmetric matter at high densities are not sufficient to pin down the composition, if uncertainties on measurements are accounted for. We conclude that only constraints on the symmetry energy at high densities can make some meaningful impact to decipher the composition of neutron star core. Our results give a lower limit to the uncertainty on the NS core composition that can be obtained with astrophysical and terrestrial experiments.

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C. Mondal and F. Gulminelli
Tue, 9 Nov 21
53/102

Comments: 6 pages, 5 figures

A New Semi-Empirical Model for Cosmic Ray Muon Flux Estimation [IMA]

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http://arxiv.org/abs/2110.14152


Cosmic ray muons have emerged as a non-conventional high-energy radiation probe to monitor dense and large objects. Muons are the most abundant cosmic radiation on Earth, however, their flux at sea level is approximately 10,000/min-m2 much less than that of induced radiation, i.e., x-rays or electron beams. Cosmic ray muon flux varies with the particle incident angle and it is frequently approximated using a cosine-squared which can introduce large errors for high zenith angles. However, the cosmic ray muon flux depends on not only the zenith angle but also on the effective solid angle and the geometric characteristics of the detectors. Since the low muon flux typically results in long measurement times, an accurate estimation of the measurable muon counts is important for many muon applications. Here we propose a simple and versatile semi-empirical model to improve the accuracy in muon flux estimation at all zenith angles by incorporating the geometric parameters of detectors. We call this the Effective solid angle model. To demonstrate the functionality of our model, we compare with i) cosmic ray muon measurements, ii) the cosine-squared model, and iii) Monte-Carlo simulations. Our results show that the muon count rate estimation capability is significantly improved resulting in a reduced mean relative error from 30 % (for the cosine-squared model) to less than 15 % for the effective solid angle model. In addition, this model is simple enough and works universally for all detector geometries and configurations. By selecting an appropriate intensity correlation, the model can be easily extended to estimate muon flux at any altitude and underground level. Finally, a simple empirical correlation is derived in order to compute the expected cosmic ray muon counts in a single step.

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J. Bae and S. Chatzidakis
Thu, 28 Oct 21
30/76

Comments: N/A

Probing dense matter physics with transiently-accreting neutron stars: the case of source MXB 1659-29 [CL]

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http://arxiv.org/abs/2110.11077


Recent observational data on transiently-accreting neutron stars has unequivocally shown fast-cooling sources, such as in the case of neutron star MXB 1659-29. Previous calculations have estimated its total neutrino luminosity and heat capacity, as well as suggested that direct Urca reactions take place in $1 \%$ of the volume of the core. In this paper, we reproduce the inferred luminosity of this source with detailed models of equations of state (EOS) and nuclear pairing gaps. We show that three superfluidity gap models are inconsistent with data for all EOS and another three are disfavoured because of fine tuning arguments. We also calculate the total heat capacity for all constructed stars and show that independent observations of mass and luminosity could set constraints on the core superfluidity of a source as well as the density slope of the symmetry energy, L. This is an important step towards defining a universal equation of state for neutron stars and therefore, towards a better understanding of the phase diagram of asymmetric matter at high densities.

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M. Mendes, F. Fattoyev, A. Cumming, et. al.
Tue, 26 Oct 21
68/109

Comments: Talk given at the XVI Marcel Grossmann Meeting (2021), to be published on their proceedings

Evidence for a QCD accelerator in relativistic heavy-ion collisions [CL]

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http://arxiv.org/abs/2110.09432


We report measurements of forward jets produced in Cu+Au collisions at $\sqrt{s_{NN}}=200$ GeV at the Relativistic Heavy Ion Collider. The jet-energy distributions extend to energies much larger than expected by Feynman scaling. This constitutes the first clear evidence for Feynman-scaling violations in heavy-ion collisions. Such high-energy particle production has been in models via QCD string interactions, but so far is untested by experiment. One such model calls this a hadronic accelerator. Studies with a particular heavy-ion event generator (HIJING) show that photons and mesons exhibit such very high-energy production in a heavy-ion collision, so {\it QCD accelerator} appropriately captures the physics associated with such QCD string interactions. All models other than HIJING used for hadronic interactions in the study of extensive air showers from cosmic rays either do not include these QCD string interactions, or have smaller effects from the QCD accelerator.

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L. Bland, E. Brash, H. Crawford, et. al.
Tue, 19 Oct 21
79/98

Comments: Submitted to Phys. Rev. C

Supernova Preshock Neutronization Burst as a Probe of Non-Standard Neutrino Interactions [HEAP]

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http://arxiv.org/abs/2110.07249


It is believed that there is a preshock neutronization burst of $\nu_e$ before the shock-breakout burst in a core-collapse supernova (CCSN). The preshock burst essentially consists of only $\nu_e$ produced from the electron capture of nuclei in the early stage of the core collapse and is sensitive to the low-energy coherent elastic neutrino-nucleus scattering (CE$\nu$NS) which dominates the neutrino opacity and significantly influences the early $\nu_e$ emission in the CCSN. Since the CE$\nu$NS depends strongly on the largely uncertain non-standard neutrino interactions (NSI), the detection of the preshock burst thus provides a clean way to extract the NSI information. Within the spherically symmetric general-relativistic hydrodynamic simulation for the CCSN, we investigate the NSI effects on the preshock burst. We find that the NSI can maximally enhance the peak luminosity of the preshock burst almost by a factor of three, reaching a value to be comparable with that of the shock-breakout burst. The future detection of the preshock burst will have critical implications on astrophysics, neutrino physics and physics beyond the standard model.

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X. Huang, S. Zha and L. Chen
Fri, 15 Oct 21
1/56

Comments: 5 pages, 3 figures

Nuclear Shell Structure in a Finite-Temperature Relativistic Framework [CL]

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http://arxiv.org/abs/2110.05749


The shell evolution of neutron-rich nuclei with temperature is studied in a beyond-mean-field framework rooted in the meson-nucleon Lagrangian. The temperature-dependent Dyson equation with the dynamical kernel taking into account the particle-vibration coupling (PVC) is solved for the fermionic propagators in the basis of the thermal relativistic mean-field Dirac spinors. The calculations are performed for $^{68-78}$Ni in a broad range of temperatures $0 \leq T \leq 4$ MeV. The special focus is put on the fragmentation pattern of the single-particle states, which is further investigated within toy models in strongly truncated model spaces. Such models allow for quantifying the sensitivity of the fragmentation to the phonon frequencies, the PVC strength and to the mean-field level density. The model studies provide insights into the temperature evolution of the PVC mechanism in real nuclear systems under the conditions which may occur in astrophysical environments.

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H. Wibowo and E. Litvinova
Wed, 13 Oct 21
71/80

Comments: Article: 17 pages, 19 figures

Enhanced symmetry energy bears universality of the r-process [HEAP]

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http://arxiv.org/abs/2110.00713


The abundance of about half of the stable nuclei heavier than iron via the rapid neutron capture process or $r$-process is intimately related to the competition between neutron capture and $\beta$-decay rates, which ultimately depends on the binding energy of neutron-rich nuclei. The well-known Bethe-Weizs\”acker semi-empirical mass formula\cite{weiz,bethe} describes the binding energy of ground states — i.e. nuclei with temperatures of $T\approx0$ MeV — with the symmetry energy parameter converging between $23-27$ MeV for heavy nuclei. Here we find an unexpected enhancement of the symmetry energy at higher temperatures, $T\approx0.7-1.0$ MeV, from the available data of giant dipole resonances built on excited states. Although these are likely the temperatures where seed elements are created — during the cooling down of the ejecta following neutron-star mergers\cite{mergersnucleo} or collapsars\cite{collapsar} — the fact that the symmetry energy remains constant between $T\approx0.7-1.0$ MeV, suggests a similar trend down to $T\approx0.5$ MeV, where neutron-capture may start occurring. Calculations using this relatively larger symmetry energy yield a reduction of the binding energy per nucleon for heavy neutron-rich nuclei and inhibits radiative neutron-capture rates. This results in a substantial close in of the neutron dripline — where nuclei become unbound — which elucidates the long sought universality of heavy-element abundances through the $r$-process; as inferred from the similar abundances found in extremely metal-poor stars and the Sun.

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J. Orce, B. Dey, C. Ngwetsheni, et. al.
Tue, 5 Oct 21
29/72

Comments: 7 pages, 10 figures

Nuclear fusion catalyzed by doubly charged scalars: Implications for energy production [CL]

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http://arxiv.org/abs/2109.13960


A number of popular extensions of the Standard Model of particle physics predict the existence of doubly charged scalar particles $X^{\pm\pm}$. Such particles may be long-lived or even stable. If exist, $X^{–}$ could form atomic bound states with light nuclei and catalyze their fusion by essentially eliminating the Coulomb barrier between them. Such an $X$-catalyzed fusion ($X$CF) process does not require high temperatures or pressure and may have important applications for energy production. A similar process of muon-catalyzed fusion ($\mu$CF) has been shown not to be a viable source of energy because of the sticking of negative muons to helium nuclei produced in the fusion of hydrogen isotopes, which stops the catalytic process. We analyze $X$CF in deuterium environments and show that the $X$-particles can only stick to $^6$Li nuclei, which are produced in the third-stage reactions downstream the catalytic cycle. The corresponding sticking probability is very low, and, before getting bound to $^6$Li, each $X$-particle can catalyze $\sim 3.5\cdot 10^{9}$ fusion cycles, producing $\sim 7\cdot 10^{4}$ TeV of energy. We also discuss the ways of reactivating the $X$-particles from the Coulomb-bound (${\rm ^6Li}X$) states, which would allow re-using them in $X$CF reactions.

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E. Akhmedov
Fri, 1 Oct 21
50/65

Comments: RevTeX, 7 pages plus Supplemental material 11 pages

Systematical studies of the E1 photon strength functions combining Skyrme-HFB+QRPA model and experimental giant dipole resonance properties [CL]

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http://arxiv.org/abs/2109.13968


Valuable theoretical predictions of nuclear dipole excitations in the whole nuclear chart are of great interest for different applications, including in particular nuclear astrophysics. We present here the systematic study of the electric dipole (E1) photon strength functions (PSFs) combining the microscopic Hartree-Fock-Bogoliubov plus Quasiparticle Random Phase Approximation (HFB+QRPA) model and the parametrizations constrained by the available experimental giant dipole resonance (GDR) data. For about 10000 nuclei with 8<Z<124 lying between the proton and the neutron drip-lines on nuclear chart, the particle-hole strength distributions are computed using the HFB+QRPA model under the assumption of spherical symmetry and making use of the BSk27 Skyrme effective interaction derived from the most accurate HFB mass model (HFB-27) so far achieved. Large-scale calculations of the BSk27+QRPA E1 PSFs are performed in the framework of a specific folding procedure, in which three phenomenological improvements are considered. First, two interference factors are introduced and adjusted to reproduce at best the available experimental GDR data. Second, an empirical expression accounting for the deformation effect is applied to describe the peak splitting of the strength function. Third, the width of the strength function is corrected by a temperature-dependent term, which effectively increases the de-excitation photon strength function at low-energy. The E1 PSFs as well as the extracted GDR peaks and widths are compared with available experimental data. A relatively good agreement with data indicates the reliability of the calculations. Eventually, the astrophysical (n,g) rates for all the 10000 nuclei with 8<Z<124 are estimated using the present E1 PSFs. The resulting reaction rates are compared with previous BSk7+QRPA results and Gogny-HFB+QRPA predictions based on the D1M interaction.

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Y. Xu, S. Goriely and E. Khan
Thu, 30 Sep 21
26/82

Comments: 16 pages, 14 figures, to be published on Phys. Rev. C

The Status and Future of Direct Nuclear Reaction Measurements for Stellar Burning [CL]

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http://arxiv.org/abs/2109.14418


The study of stellar burning began just over 100 years ago. Nonetheless, we do not yet have a detailed picture of the nucleosynthesis within stars and how nucleosynthesis impacts stellar structure and the remnants of stellar evolution. Achieving this understanding will require precise direct measurements of the nuclear reactions involved. This report summarizes the status of direct measurements for stellar burning, focusing on developments of the last couple of decades, and offering a prospectus of near-future developments.

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M. Aliotta, R. Buompane, M. Couder, et. al.
Thu, 30 Sep 21
40/82

Comments: Accepted to Journal of Physics G as a Major Report. Corresponding author: Zach Meisel (meisel@ohio.edu)

Warning: The mini gamma-ray-bursts in planning hadron colliders beyond the LHC energies [CL]

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http://arxiv.org/abs/2109.09826


Gluons may converge to a stable state at a critical momentum in nucleon. This gluon condensation will greatly increase the proton-proton cross section provided that the collision energies exceed the gluon condensation threshold. Based on the analyses of cosmic gamma-ray spectra, we find that the $p-Pb$ and $Pb-Pb$ collisions at the LHC are close to the energy region of the gluon condensation effect. We warn that for the next generation of hadron colliders increasing the collision energies, the extremely strong gamma-rays will be emitted in a narrow space of the accelerator due to the gluon condensation effect. Such artificial mini gamma-ray-bursts in the laboratory may damage the detectors.

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W. Zhu, Z. Cui and J. Ruan
Wed, 22 Sep 21
28/57

Comments: 18 pages,4 figures,2 tables

The Radioactive Nuclei $^{\textbf{26}}$Al and $^{\textbf{60}}$Fe in the Cosmos and in the Solar System [HEAP]

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http://arxiv.org/abs/2109.08558


The cosmic evolution of the chemical elements from the Big Bang to the present time is driven by nuclear fusion reactions inside stars and stellar explosions. A cycle of matter recurrently re-processes metal-enriched stellar ejecta into the next generation of stars. The study of cosmic nucleosynthesis and of this matter cycle requires the understanding of the physics of nuclear reactions, of the conditions at which the nuclear reactions are activated inside the stars and stellar explosions, of the stellar ejection mechanisms through winds and explosions, and of the transport of the ejecta towards the next cycle, from hot plasma to cold, star-forming gas. Due to the long timescales of stellar evolution, and because of the infrequent occurrence of stellar explosions, observational studies are challenging. Due to their radioactive lifetime of million years, the 26Al and 60Fe isotopes are suitable to characterise simultaneously the processes of nuclear fusion reactions and of interstellar transport. We describe and discuss the nuclear reactions involved in the production and destruction of 26Al and 60Fe, the key characteristics of the stellar sites of their nucleosynthesis and their interstellar journey after ejection from the nucleosynthesis sites. We connect the theoretical astrophysical aspects to the variety of astronomical messengers, from stardust and cosmic-ray composition measurements, through observation of gamma rays produced by radioactivity, to material deposited in deep-sea ocean crusts and to the inferred composition of the first solids that have formed in the Solar System. We show that considering measurements of the isotopic ratio of 26Al to 60Fe eliminate some of the unknowns when interpreting astronomical results, and discuss the lessons learned from these two isotopes on cosmic chemical evolution.

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R. Diehl, M. Lugaro, A. Heger, et. al.
Mon, 20 Sep 21
16/53

Comments: 51 pages, 44 figures; review from an ISSI workshop series; accepted for publication in PASA

Binding energy shifts from heavy-ion experiments in a nuclear statistical equilibrium model [CL]

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http://arxiv.org/abs/2109.02961


Chemical constants extracted from $^{124}$Xe+ $^{124}$Sn collisions at 32 AMeV are compared to the predictions of an extended Nuclear Statistical Equilibrium model including mean-field interactions and in-medium binding energy shifts for the light ($Z\leq 2$) clusters. The ion species and density dependence of the in-medium modification is directly extracted from the experimental data. We show that the shift increases with the mass of the cluster and the density of the medium, and we provide a simple linear fit for future use in astrophysical simulations in the framework of the CompOSE data base. The resulting mass fractions are computed in representative thermodynamic conditions relevant for supernova and neutron star mergers. A comparison to the results of a similar analysis of the same data performed in the framework of a relativistic mean-field model shows a good agreement at low density, but significant discrepancies close to the Mott dissolution of clusters in the dense medium.

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S. Mallik, H. Pais and F. Gulminelli
Wed, 8 Sep 21
64/76

Comments: 7 pages, 4 figures

Bayesian Estimation of the D(p,$γ$)$^3$He Thermonuclear Reaction Rate [CEA]

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http://arxiv.org/abs/2109.00049


Big bang nucleosynthesis (BBN) is the standard model theory for the production of the light nuclides during the early stages of the universe, taking place for a period of about 20 minutes after the big bang. Deuterium production, in particular, is highly sensitive to the primordial baryon density and the number of neutrino species, and its abundance serves as a sensitive test for the conditions in the early universe. The comparison of observed deuterium abundances with predicted ones requires reliable knowledge of the relevant thermonuclear reaction rates, and their corresponding uncertainties. Recent observations reported the primordial deuterium abundance with percent accuracy, but some theoretical predictions based on BBN are at tension with the measured values because of uncertainties in the cross section of the deuterium-burning reactions. In this work, we analyze the S-factor of the D(p,$\gamma$)$^3$He reaction using a hierarchical Bayesian model. We take into account the results of eleven experiments, spanning the period of 1955–2021; more than any other study. We also present results for two different fitting functions, a two-parameter function based on microscopic nuclear theory and a four-parameter polynomial. Our recommended reaction rates have a 2.2\% uncertainty at $0.8$~GK, which is the temperature most important for deuterium BBN. Differences between our rates and previous results are discussed.

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J. Moscoso, R. Souza, A. Coc, et. al.
Thu, 2 Sep 21
33/59

Comments: N/A

Ab initio structure factors for spin-dependent dark matter direct detection [CL]

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http://arxiv.org/abs/2109.00193


We present converged ab initio calculations of structure factors for elastic spin-dependent WIMP scattering off all nuclei used in dark matter direct-detection searches: $^{19}$F, $^{23}$Na, $^{27}$Al, $^{29}$Si, $^{73}$Ge, $^{127}$I, and $^{129,131}$Xe. From a set of established two- and three-nucleon interactions derived within chiral effective field theory, we construct consistent WIMP-nucleon currents at the one-body level, including effects from axial-vector two-body currents. We then apply the in-medium similarity renormalization group to construct effective valence-space Hamiltonians and consistently transformed operators of nuclear responses. Combining the recent advances of natural orbitals with three-nucleon forces expressed in large spaces, we obtain basis-space converged structure factors even in heavy nuclei. Generally results are consistent with previous calculations but in certain cases can differ by as much as 80-90\% at low momentum transfer.

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B. Hu, J. Padua-Argüelles, S. Leutheusser, et. al.
Thu, 2 Sep 21
44/59

Comments: 6 pages, 3 figures, supplemental material included

Measurement of the 91Zr(p,gamma)92mNb cross section motivated by type Ia supernova nucleosynthesis [CL]

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http://arxiv.org/abs/2108.10006


The synthesis of heavy, proton rich isotopes is a poorly understood astrophysical process. Thermonuclear (type Ia) supernova explosions are among the suggested sites and the abundance of some isotopes present in the early solar system may be used to test the models. 92Nb is such an isotope and one of the reactions playing a role in its synthesis is 91Zr(p,gamma)92Nb. As no experimental cross sections were available for this reaction so far, nucleosynthesis models had to solely rely on theoretical calculations. In the present work the cross section of 91Zr(p,gamma)92mNb has been measured at astrophysical energies by activation. The results excellently confirm the predictions of cross sections and reaction rates for 91Zr(p,gamma)92Nb, as used in astrophysical simulations.

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G. Gyürky, Z. Halász, G. Kiss, et. al.
Tue, 24 Aug 21
57/76

Comments: Accepted for publication in Journal of Physics G

High-precision nuclear chronometer for the cosmos [CL]

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http://arxiv.org/abs/2108.06104


Nuclear chronometer, which predicts the ages of the oldest stars by comparing the present and initial abundances of long-lived radioactive nuclides, provides an independent dating technique for the cosmos. A new nuclear chronometer called Th-U-X chronometer is proposed, which imposes stringent constraints on the astrophysical conditions in the $r$-process simulation by synchronizing the previous Th/X, U/X and Th/U chronometers. The astrophysical uncertainties of nuclear chronometer are significantly reduced from more than $\pm2$ billion years to within 0:3 billion years by the Th-U-X chronometer. The proposed chronometer is then applied to estimate the ages of the six metal-poor stars with observed uranium abundances, and the predicted ages are compatible with the cosmic age 13.8 billion years predicted from the cosmic microwave background radiation, but in contradictory with the new cosmic age 11.4 billion years from the gravitational lenses measurement.

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X. Wu, P. Zhao, S. Zhang, et. al.
Mon, 16 Aug 21
4/34

Comments: 5 pages, 4 figures

The 27Al(p,a)24Mg reaction at astrophysical energies studied by means of the Trojan Horse Method applied to the 2H(27Al,a24Mg)n reaction [CL]

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http://arxiv.org/abs/2108.06145


The 27Al(p,a)24Mg reaction, which drives the destruction of 27Al and the production of 24Mg in stellar hydrogen burning, has been investigated via the Trojan Horse Method (THM) by measuring the 2H(27Al,a24Mg)n three-body reaction. The experiment covered a broad energy range (-0.5 MeV < E_cm < 1.5 MeV), aiming to investigate those of interest for astrophysics.The results confirm the THM as a valuable technique for the experimental study of fusion reactions at very low energies and suggest the presence of a rich pattern of resonances in the energy region close to the Gamow window of stellar hydrogen burning (70-120 keV), with potential impact on astrophysics. To estimate such an impact a second run of the experiment is needed, since the background due the three-body reaction hampered to collect enough data to resolve the resonant structures and extract the reaction rate.

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S. Palmerini, M. Cognata, F. Hammache, et. al.
Mon, 16 Aug 21
17/34

Comments: 8 pages, accepted for publication by EPJ Plus

Advancement of photospheric radius expansion and clocked type-I x-ray burst models with the new $^{22}$Mg$(α,p)^{25}$Al reaction rate determined at Gamow energy [CL]

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http://arxiv.org/abs/2108.04553


We report the first (in)elastic scattering measurement of $^{25}\mathrm{Al}+p$ with the capability to select and measure in a broad energy range the proton resonances in $^{26}$Si contributing to the $^{22}$Mg$(\alpha,p)$ reaction at type I x-ray burst energies. We measured spin-parities of four resonances above the $\alpha$ threshold of $^{26}$Si that are found to strongly impact the $^{22}$Mg$(\alpha,p)$ rate. The new rate advances a state-of-the-art model to remarkably reproduce lightcurves of the GS 1826$-$24 clocked burster with mean deviation $<$9 % and permits us to discover a strong correlation between the He abundance in the accreting envelope of photospheric radius expansion burster and the dominance of $^{22}$Mg$(\alpha,p)$ branch.

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J. Hu, H. Yamaguchi, Y. Lam, et. al.
Wed, 11 Aug 21
67/72

Comments: accepted by Physical Review Letters on 5 August 2021

Progress in Nuclear Astrophysics of East and Southeast Asia [CL]

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http://arxiv.org/abs/2108.03814


Nuclear astrophysics is an interdisciplinary research field of nuclear physics and astrophysics, seeking for the answer to a question, how to understand the evolution of the Universe with the nuclear processes which we learn. We review the research activities of nuclear astrophysics in east and southeast Asia which includes astronomy, experimental and theoretical nuclear physics and astrophysics. Several hot topics such as the Li problems, critical nuclear reactions and properties in stars, properties of dense matter, r-process nucleosynthesis and $\nu$-process nucleosynthesis are chosen and discussed in further details. Some future Asian facilities, together with physics perspectives, are introduced.

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A. Aziz, N. Ahmad, S. Ahn, et. al.
Tue, 10 Aug 21
60/84

Comments: 49 pages, 10 figures, published in AAPPS (Association of Asia Pacific Physical Societies) Bulletin

Role of ambient humidity underestimated in research on correlation between radioactive decay rates and space weather [CL]

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http://arxiv.org/abs/2108.00116


In recent work, Milian-Sanchez et al. observed fluctuations in radioactive decay rate measurement series, and after excluding environmental influences (measured indoors) as root causes, they looked for possible correlations with astrophysical variables. In spite of the authors efforts to investigate possible influences of environmental parameters (such as ambient temperature, pressure and humidity) on the detectors stability, it turns out that the influence of ambient humidity on the instrumentation has been underestimated.

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S. Pommé and K. Pelczar
Tue, 3 Aug 21
52/90

Comments: 6 pages, 1 figure

Results from a Pilot Study on the Measurement of Nuclear Fragmentation with NA61/SHINE at the CERN SPS: $^{11}\text{C}$ Production in $\text{C+p}$ Interactions at 13.5 A GeV/c [CL]

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http://arxiv.org/abs/2107.12275


We report the analysis of data taken during a pilot run in 2018 to study the feasibility of nuclear fragmentation measurements with the NA61/SHINE experiment at the CERN SPS. These nuclear reactions are important for the interpretation of secondary cosmic-ray nuclei production (Li, Be, and B) in the Galaxy. The pilot data were taken with $^{12}\text{C}$ projectiles at a beam momentum of 13.5 A GeV/c and two fixed targets, polyethylene (C$_2$H$_4$) and graphite. The specific focus here is the measurement of total Boron ($^{10}\text{B}$ and $^{11}\text{B}$) production cross section in $\text{C+p}$ interactions at 13.5 A GeV/c. The cosmic-ray nucleus $^{11}\text{C}$ is termed a `Ghost nucleus’ on account of its short lifetime compared to the usual cosmic-ray diffusion time in the Galaxy and it ultimately decays to Boron as, $^{11}\text{C} \to ^{11}\text{B} + \beta^+$. Therefore, precise knowledge of the production cross section of $^{11}\text{C}$ is very relevant for the understanding of Boron production in the Galaxy. We present a preliminary measurement of the fragmentation cross section of $\text{C+p}\to ^{11}\text{C}$, which, together with our previously reported B-production cross section, provides a new constraint on Boron production in the Galaxy in the high-energy range relevant for modern space based cosmic-ray experiments like AMS-02.

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N. Amin
Tue, 27 Jul 21
89/97

Comments: 9 pages, 9 figures, Presented at the 37th International Cosmic Ray Conference (ICRC 2021)

The Future of Solar Neutrinos [CL]

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http://arxiv.org/abs/2107.08613


In this article we review the current state of the field of solar neutrinos, including flavour oscillations, non-standard effects, solar models, cross section measurements, and the broad experimental program thus motivated and enabled. We discuss the historical discoveries that contributed to current knowledge, and define critical open questions to be addressed in the next decade. We discuss the state of the art of standard solar models, including uncertainties and problems related to the solar composition, and review experimental and model solar neutrino fluxes, including future prospects. We review the state of the art of the nuclear reaction data relevant for solar fusion in the proton-proton chain and carbon-nitrogen-oxygen cycle. Finally, we review the current and future experimental program that can address outstanding questions in this field.

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G. Gann, K. Zuber, D. Bemmerer, et. al.
Tue, 20 Jul 21
86/104

Comments: N/A

Constraining Neutron-Star Matter with Microscopic and Macroscopic Collisions [CL]

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http://arxiv.org/abs/2107.06229


Interpreting high-energy, astrophysical phenomena, such as supernova explosions or neutron-star collisions, requires a robust understanding of matter at supranuclear densities. However, our knowledge about dense matter explored in the cores of neutron stars remains limited. Fortunately, dense matter is not only probed in astrophysical observations, but also in terrestrial heavy-ion collision experiments. In this work, we use Bayesian inference to combine data from astrophysical multi-messenger observations of neutron stars and from heavy-ion collisions of gold nuclei at relativistic energies with microscopic nuclear theory calculations to improve our understanding of dense matter. We find that the inclusion of heavy-ion collision data indicates an increase in the pressure in dense matter relative to previous analyses, shifting neutron-star radii towards larger values, consistent with recent NICER observations. Our findings show that constraints from heavy-ion collision experiments show a remarkable consistency with multi-messenger observations and provide complementary information on nuclear matter at intermediate densities. This work combines nuclear theory, nuclear experiment, and astrophysical observations, and shows how joint analyses can shed light on the properties of neutron-rich supranuclear matter over the density range probed in neutron stars.

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S. Huth, P. Pang, I. Tews, et. al.
Wed, 14 Jul 21
43/67

Comments: 7 pages, 2 figures, Supplemental Material

A Detailed Examination of Astrophysical Constraints on the Symmetry Energy and the Neutron Skin of $^{208}$Pb with Minimal Modeling Assumptions [CL]

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http://arxiv.org/abs/2107.05528


The symmetry energy and its density dependence are pivotal for many nuclear physics and astrophysics applications, as they determine properties ranging from the neutron-skin thickness of nuclei to the crust thickness and the radius of neutron stars. Recently, PREX-II reported a value of $0.283\pm0.071$ fm for the neutron-skin thickness of $^{208}$Pb, $R_{\rm skin}^{^{208}\text{Pb}}$, implying a symmetry-energy slope parameter $L$ of $106\pm37$ MeV, larger than most ranges obtained from microscopic calculations and other nuclear experiments. We use a nonparametric equation of state representation based on Gaussian processes to constrain the symmetry energy $S_0$, $L$, and $R_{\rm skin}^{^{208}\text{Pb}}$ directly from observations of neutron stars with minimal modeling assumptions. The resulting astrophysical constraints from heavy pulsar masses, LIGO/Virgo, and NICER favor smaller values of the neutron skin and $L$, as well as negative symmetry incompressibilities. Combining astrophysical data with chiral effective field theory ($\chi$EFT) and PREX-II constraints yields $S_0 = 33.0^{+2.0}{-1.8}$ MeV, $L=53^{+13}{-15}$ MeV, and $R_{\rm skin}^{^{208}\text{Pb}} = 0.17^{+0.04}{-0.04}$ fm. We also examine the consistency of several individual $\chi$EFT calculations with astrophysical observations and terrestrial experiments. We find that there is only mild tension between $\chi$EFT, astrophysical data, and PREX-II’s $R\mathrm{skin}^{^{208}\mathrm{Pb}}$ measurement ($p$-value $= 12.3\%$) and that there is excellent agreement between $\chi$EFT, astrophysical data, and other nuclear experiments.

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R. Essick, P. Landry, A. Schwenk, et. al.
Tue, 13 Jul 21
12/79

Comments: 18 pages, 12 figures, 1 table

Relationships among detector signals recorded during events SN1987A and GW170817 [CL]

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http://arxiv.org/abs/2107.00265


The temporal coincidences of events detected in four neutrino detectors and two gravitational antennas still remains among the most puzzling phenomena associated with SN1987A. The coincidences form a six-hour signal approximately coincident in time with the well-known LSD signal at 2h52m UT on 23/02/1987. After 30 years of research, the characteristics and the shape of the six-hour signal have been studied quite well, but the mechanisms of its formation have not been fully understood as of yet. Here we suggest that data obtained from another technology, radioactive decays, might provide new insights into the origin of signals previously seen in neutrino detectors and gravity wave detectors. On August 17, 2017, at 12h41m UT, the GW170817 signal was detected by LIGO and Virgo. At the same time, an approximately 7-hour long signal coincident with GW170817 was detected in the Si/Cl experiment on precision measurement of the $^{32}$Si half-life. We show that the Si/Cl signal is unexpectedly similar to the six-hour signal from SN1987A. In addition, we establish that the sources of the coinciding events are similar to those of the Si/Cl signal. To explain the surprising similarities in both signals, we present a mechanism which could in principle account for this phenomenon in terms of a local increase in the density of axionic dark matter induced by a gravity wave.

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N. Agafonova, A. Malgin and E. Fischbach
Fri, 2 Jul 21
36/67

Comments: 8 pages, 5 figures, 3 tables. This is the author’s version and not the final typeset

The unfinished fabric of the three neutrino paradigm [CL]

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http://arxiv.org/abs/2107.00532


In the current 3nu paradigm, flavor oscillations probe 3 mixing angles (theta_12, theta_23, theta_13), one CP phase delta, and two squared mass differences delta m^2>0 and Delta m^2, where sign(Delta m^2)=+ (-) for normal (inverted) ordering. Absolute nu masses can be probed by the effective m_beta in beta decay, by the total mass Sigma in cosmology and, if neutrinos are Majorana, by another effective m_{beta beta} in 0nu2beta decay. Within an updated global analysis of (non)oscillation data, we constrain these 3nu parameters, both separately and in selected pairs, and highlight the concordance or discordance among different constraints. Five oscillation parameters (delta m^2, Delta m^2, theta_12, theta_23, theta_13) are consistently measured, with an overall accuracy ranging from ~1% for Delta m^2 to ~6% for sin^2(theta_23) (due to its octant ambiguity). We find overall hints for normal ordering (at 2.5 sigma), as well as for theta_23<pi/4 and for sin(delta)<0 (both at 90% C.L.), and discuss some tensions among datasets. Concerning nonoscillation data, we include the recent KATRIN constraints on m_beta, and we combine the latest 76-Ge, 130-Te and 136-Xe bounds on m_{beta beta}, accounting for NME covariances. We also discuss some variants related to CMB anisotropy and lensing data, which may affect cosmological constraints on Sigma and hints on sign(Delta m^2). The default option, including all Planck results, irrespective of the lensing anomaly, sets upper bounds on Sigma at the level of ~10^-1 eV, and further favors normal ordering up to ~3 sigma. An alternative option, that includes recent ACT results + other independent results (from WMAP and selected Planck data) globally consistent with standard lensing, is insensitive to the ordering but prefers Sigma ~(few) x 10^-1 eV, with different implications for m_beta and m_{beta beta} searches. (Abridged)

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F. Capozzi, E. Valentino, E. Lisi, et. al.
Fri, 2 Jul 21
60/67

Comments: 22 pages, including 16 figures

Development of very-thick transparent GEMs with wavelength-shifting capability for noble element TPCs [CL]

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http://arxiv.org/abs/2106.03773


A new concept for the simultaneous detection of primary and secondary scintillation in time projection chambers is proposed. Its core element is a type of very-thick GEM structure supplied with transparent electrodes and machined from a polyethylene naphthalate plate, a natural wavelength-shifter. Such a device has good prospects for scalability and, by virtue of its genuine optical properties, it can improve on the light collection efficiency, energy threshold and resolution of conventional micropattern gas detectors. This, together with the intrinsic radiopurity of its constituting elements, offers advantages for noble gas and liquid based time projection chambers, used for dark matter searches and neutrino experiments. Production, optical and electrical characterization, and first measurements performed with the new device are reported.

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M. Kuźniak, D. González-Díaz, P. Amedo, et. al.
Mon, 21 Jun 21
13/54

Comments: accepted for publication in Eur. Phys. J. C

Decoding the Density Dependence of the Nuclear Symmetry Energy [CL]

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http://arxiv.org/abs/2106.10119


The large imbalance in the neutron and proton densities in very neutron rich systems increases the nuclear symmetry energy so that it governs many aspects of neutron stars and their mergers. Extracting the density dependence of the symmetry energy therefore constitutes an important scientific objective. Many analyses have been limited to extracting values for the symmetry energy, $S_0$, and its “derivative”, $L$, at saturation density $\rho_0 \approx 2.6 \times 10^{14}~\mathrm{g/cm^3}$ $\approx 0.16~\mathrm{nucleons/fm^{3}}$, resulting in constraints that appear contradictory. We show that most experimental observables actually probe the symmetry energy at densities far from $\rho_0$, making the extracted values of $S_0$ or $L$ imprecise. By focusing on the densities these observables actually probe, we obtain a detailed picture of the density dependence of the symmetry energy from $0.25\rho_0$ to $1.5\rho_0$. From this experimentally derived density functional, we extract $L_{01}=53.1\pm6.1 MeV$ at $\rho \approx 0.10~\mathrm{fm^{-3}}$, a neutron skin thickness for $^{208}Pb$ of $R_{np} =$ $0.23\pm0.04$ fm, a symmetry pressure at saturation density of $P_0=3.2\pm1.2 MeV/fm^3$ and suggests a radius for a 1.4 solar mass neutron star of $13.1\pm0.6$ km.

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W. Lynch and M. Tsang
Mon, 21 Jun 21
52/54

Comments: 6 pages, 4 figures

Impacts of NICER's Radius Measurement of PSR J0740+6620 on Nuclear Symmetry Energy at Suprasaturation Densities [CL]

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http://arxiv.org/abs/2105.11031


By directly inverting several neutron star observables in the three-dimensional parameter space for the Equation of State of super-dense neutron-rich nuclear matter, we show that the lower radius limit $R_{2.01}\geq 12.2$ km at 68\% confidence level for PSR J0740+6620 of mass $2.08\pm 0.07~M_{\odot}$ from Neutron Star Interior Composition Explorer (NICER)’s very recent observation sets a much tighter lower boundary than previously known for nuclear symmetry energy in the density range of $(1.0\sim 3.0)$ times the saturation density $\rho_0$ of nuclear matter. The super-soft symmetry energy leading to the formation of proton polarons in this density region of neutron stars is firmly ruled out by the first radius measurement for the most massive neutron star observed reliably so far.

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N. Zhang and B. Li
Tue, 25 May 21
74/75

Comments: 9 pages including 6 figures

Fission fragment distributions of neutron-rich nuclei based on Langevin calculations: toward r-process simulations [CL]

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http://arxiv.org/abs/2105.09272


The nuclear fission of very neuron-rich nuclei related to the r-process is essential for the termination of nucleosynthesis flows on the nuclear chart and the final abundances. Nevertheless, most of the available fission data for the r-process calculations are based on theory predictions, including phenomenological treatments. In this study, we calculated a series of nuclear fission distribution for neutron-rich nuclei away from the beta-stability line. As most of these nuclei are experimentally unknown, we are based on theoretical calculations based on the dynamical fission model with the Langevin method. We performed fission distribution calculations for neutron-rich actinoid nuclei, applicable to the r-process nucleosynthesis simulations. In the present paper, we compared the obtained mass and charge distributions with experimental data. We also show the results of the systematic behaviour of mass distribution for neutron-rich U and Fm isotopes.

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M. Okubayashi, S. Tanaka, Y. Aritomo, et. al.
Thu, 20 May 21
2/56

Comments: 6 pages, 5 figures, to be published in the conference proceedings of “Symposium on Nuclear Data 2020”

Nuclear-Physics Multi-Messenger Astrophysics Constraints on the Neutron-Star Equation of State: Adding NICER's PSR J0740+6620 Measurement [HEAP]

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http://arxiv.org/abs/2105.08688


In the past few years, new observations of neutron stars and neutron-star mergers have provided a wealth of data that allow one to constrain the equation of state of nuclear matter at densities above nuclear saturation density. However, most observations were based on neutron stars with masses of about 1.4 solar masses, probing densities up to $\sim$ 3-4 times the nuclear saturation density. Even higher densities are probed inside massive neutron stars such as PSR J0740+6620. Very recently, new radio observations provided an update to the mass estimate for PSR J0740+6620 and X-ray observations by the NICER and XMM telescopes constrained its radius. Based on these new measurements, we revisit our previous nuclear-physics multi-messenger astrophysics constraints and derive updated constraints on the equation of state describing the neutron-star interior. By combining astrophysical observations of two radio pulsars, two NICER measurements, the two gravitational-wave detections GW170817 and GW190425, detailed modeling of the kilonova AT2017gfo, as well as the gamma-ray burst GRB170817A, we are able to estimate the radius of a typical 1.4-solar mass neutron star to be $11.94^{+0.76}_{-0.87} \rm{km}$ at 90\% confidence. Our analysis allows us to revisit the upper bound on the maximum mass of neutron stars and disfavours the presence of a strong first-order phase transition from nuclear matter to exotic forms of matter, such as quark matter, inside neutron stars.

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P. Pang, I. Tews, M. Coughlin, et. al.
Wed, 19 May 21
12/64

Comments: 12 pages, 5 figures

Measurements of $^{160}$Dy($p,γ$) at energies relevant for astrophysical $γ$ process [CL]

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http://arxiv.org/abs/2105.07249


Rare information on photodisintegration reactions of nuclei with mass numbers $A \approx 160$ at astrophysical conditions impedes our understanding of the origin of $p$-nuclei. Experimental determination of the key ($p,\gamma$) cross sections has been playing an important role to verify nuclear reaction models and to provide rates of relevant ($\gamma,p$) reactions in $\gamma$-process. In this paper we report the first cross section measurements of $^{160}$Dy($p,\gamma$)$^{161}$Ho and $^{161}$Dy($p,n$)$^{161}$Ho in the beam energy range of 3.4 – 7.0 MeV, partially covering the Gamow window. Such determinations are possible by using two targets with various isotopic fractions. The cross section data can put a strong constraint on the nuclear level densities and gamma strength functions for $A \approx$ 160 in the Hauser-Feshbach statistical model. Furthermore, we find the best parameters for TALYS that reproduce the A $\thicksim$ 160 data available, $^{160}$Dy($p,\gamma$)$^{161}$Ho and $^{162}$Er($p,\gamma$)$^{163}$Tm, and recommend the constrained $^{161}$Ho($\gamma,p$)$^{160}$Dy reaction rates over a wide temperature range for $\gamma$-process network calculations. Although the determined $^{161}$Ho($\gamma$, p) stellar reaction rates at the temperature of 1 to 2 GK can differ by up to one order of magnitude from the NON-SMOKER predictions, it has a minor effect on the yields of $^{160}$Dy and accordingly the $p$-nuclei, $^{156,158}$Dy. A sensitivity study confirms that the cross section of $^{160}$Dy($p$, $\gamma$)$^{161}$Ho is measured precisely enough to predict yields of $p$-nuclei in the $\gamma$-process.

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H. Cheng, B. Sun, L. Zhu, et. al.
Tue, 18 May 21
42/77

Comments: 12 pages,9 figures

The Radius of PSR J0740+6620 from NICER and XMM-Newton Data [HEAP]

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http://arxiv.org/abs/2105.06979


PSR J0740$+$6620 has a gravitational mass of $2.08\pm 0.07~M_\odot$, which is the highest reliably determined mass of any neutron star. As a result, a measurement of its radius will provide unique insight into the properties of neutron star core matter at high densities. Here we report a radius measurement based on fits of rotating hot spot patterns to Neutron Star Interior Composition Explorer (NICER) and X-ray Multi-Mirror (XMM-Newton) X-ray observations. We find that the equatorial circumferential radius of PSR J0740$+$6620 is $13.7^{+2.6}{-1.5}$ km (68%). We apply our measurement, combined with the previous NICER mass and radius measurement of PSR J0030$+$0451, the masses of two other $\sim 2~M\odot$ pulsars, and the tidal deformability constraints from two gravitational wave events, to three different frameworks for equation of state modeling, and find consistent results at $\sim 1.5-3$ times nuclear saturation density. For a given framework, when all measurements are included the radius of a $1.4~M_\odot$ neutron star is known to $\pm 4$% (68% credibility) and the radius of a $2.08~M_\odot$ neutron star is known to $\pm 5$%. The full radius range that spans the $\pm 1\sigma$ credible intervals of all the radius estimates in the three frameworks is $12.45\pm 0.65$ km for a $1.4~M_\odot$ neutron star and $12.35\pm 0.75$ km for a $2.08~M_\odot$ neutron star.

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M. Miller, F. Lamb, A. Dittmann, et. al.
Mon, 17 May 21
15/55

Comments: 49 pages, 16 figures, submitted to The Astrophysical Journal Letters

Progress in Constraining Nuclear Symmetry Energy Using Neutron Star Observables since GW170817 [CL]

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http://arxiv.org/abs/2105.04629


New observational data of neutron stars since GW170817 have helped improve our knowledge about nuclear symmetry energy especially at high densities. We have learned particularly: (1) The slope parameter $L$ of nuclear symmetry energy at saturation density $\rho_0$ of nuclear matter from 24 new analyses is about $L\approx 57.7\pm 19$ MeV at 68\% confidence level consistent with its fiducial value, (2) The curvature $K_{\rm{sym}}$ from 16 new analyses is about $K_{\rm{sym}}\approx -107\pm 88$ MeV, (3) The magnitude of nuclear symmetry energy at $2\rho_0$, i.e. $E_{\rm{sym}}(2\rho_0)\approx 51\pm 13$ MeV at 68\% confidence level, has been extracted from 9 new analyses of neutron star observables consistent with results from earlier analyses of heavy-ion reactions and the latest predictions of the state-of-the-art nuclear many-body theories, (4) while the available data from canonical neutron stars do not provide tight constraints on nuclear symmetry energy at densities above about $2\rho_0$, the lower radius boundary $R_{2.01}=12.2$ km from NICER’s very recent observation of PSR J0740+6620 of mass $2.08\pm 0.07$ $M_{\odot}$ and radius $R=12.2-16.3$ km at 68\% confidence level sets a tight lower limit for nuclear symmetry energy at densities above $2\rho_0$, (5) Bayesian inferences of nuclear symmetry energy using models encapsulating a first-order hadron-quark phase transition from observables of canonical neutron stars indicate that the phase transition shift appreciably both the $L$ and $K_{\rm{sym}}$ to higher values but with larger uncertaintie , (6) The high-density behavior of nuclear symmetry energy affects significantly the minimum frequency necessary to rotationally support GW190814’s secondary component of mass (2.50-2.67) $M_{\odot}$ as the fastest and most massive pulsar discovered so far.

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B. Li, B. Cai, W. Xie, et. al.
Wed, 12 May 21
35/67

Comments: 40 pages. Invited Review for Universe in the special issue “Neutron Stars and Gravitational Wave Observations” edited by Ignazio Bombaci and Rosa Poggiani

r-Process Radioisotopes from Near-Earth Supernovae and Kilonovae [HEAP]

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http://arxiv.org/abs/2105.05178


The astrophysical sites where r-process elements are synthesized remain mysterious: it is clear that neutron-star mergers (kilonovae, KNe) contribute, and some classes of core-collapse supernovae (SNe) are also likely sources of at least the lighter r-process species. The discovery of the live isotope Fe60 on the Earth and Moon implies that one or more astrophysical explosions occurred near the Earth within the last few Myr, probably a SN. Intriguingly, several groups have reported evidence for deposits of Pu244, some overlapping with the Fe60 pulse. However, the putative Pu244 flux appears to extend to at least 12 Myr ago, pointing to a different origin. Motivated by this observation, we propose that ejecta from a KN enriched the giant molecular cloud that gave rise to the Local Bubble in which the Sun resides. Accelerator Mass Spectrometry (AMS) measurements of Pu244 and searches for other live isotopes could probe the origins of the r-process and the history of the solar neighborhood, including triggers for mass extinctions, e.g., at the end of the Devonian epoch, motivating the calculations of the abundances of live r-process radioisotopes produced in SNe and KNe that we present here. Given the presence of Pu244, other r-process species such as Zr93, Pd107, I129, Cs135, Hf182, U236, Np237 and Cm247 should be present. Their abundances could distinguish between SN and KN scenarios, and we discuss prospects for their detection in deep-ocean deposits and the lunar regolith. We show that AMS I129 measurements in Fe-Mn crusts already constrain a possible nearby KN scenario.

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X. Wang, A. Clark, J. Ellis, et. al.
Wed, 12 May 21
62/67

Comments: 43 pages,15 figures, 11 tables, comments welcome

Isospin effect on quark matter instabilities [CL]

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http://arxiv.org/abs/2104.12971


We have studied in the mechanical and chemical instabilities as well as the liquid-gas phase transition in isospin asymmetric quark matter based on the NJL and the pNJL model. Areas of the mechanical instability region and the liquid-gas coexistence region are seen to be enlarged with a larger quark matter symmetry energy or in the presence of strange quarks. Our study shows that the light cluster yield ratio observed in relativistic heavy-ion collisions may not be affected much by the uncertainties of the isospin effect, while the hadron-quark phase transition in compact stars as well as their mergers is likely to be a smooth one.

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L. Liu, W. Zhou, J. Xu, et. al.
Wed, 28 Apr 21
22/60

Comments: 8 pages, 7 figures

"In-System" Fission-Events: An Insight into Puzzles of Exoplanets and Stars? [SSA]

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http://arxiv.org/abs/2104.11744


In expansion of our recent proposal (Physics, 2020, 2, 213-276) that the solar system’s evolution occurred in two stages — during the first stage, the gaseous giants formed (via disk instability), and, during the second stage (caused by an encounter with a particular stellar-object leading to “in-system” fission-driven nucleogenesis), the terrestrial planets formed (via accretion) — we emphasize here that the mechanism of formation of such stellar-objects is generally universal and therefore encounters of such objects with stellar-systems may have occurred elsewhere across galaxies. If so, their aftereffects may perhaps be observed as puzzling features in the spectra of individual stars (such as idiosyncratic chemical enrichments) and/or in the structures of exoplanetary systems (such as unusually high planet densities or short orbital periods). This paper reviews and reinterprets astronomical data within the “fission-events framework.” Classification of stellar systems as “pristine” or “impacted” is offered.

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E. Tito and V. Pavlov
Mon, 26 Apr 21
40/45

Comments: Review, 26 pages, 13 figures

UCGretina GEANT4 Simulation of the GRETINA Gamma-Ray Energy Tracking Array [CL]

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http://arxiv.org/abs/2104.09986


UCGretina, a GEANT4 simulation of the GRETINA gamma-ray tracking array of highly-segmented high-purity germanium detectors is described. We have developed a model of the array, in particular of the Quad Module and the capsules, that gives good agreement between simulated and measured photopeak efficiencies over a broad range of gamma-ray energies and reproduces the shape of the measured Compton continuum. Both of these features are needed in order to accurately extract gamma-ray yields from spectra collected in in-beam gamma-ray spectroscopy measurements with beams traveling at $v/c \gtrsim 0.3$ at the National Superconducting Cyclotron Laboratory and the Facility for Rare Isotope Beams. In the process of developing the model, we determined that millimeter-scale layers of passive germanium surrounding the active volumes of the simulated crystals must be included in order to reproduce measured photopeak efficiencies. We adopted a simple model of effective passive layers and developed heuristic methods of determining passive-layer thicknesses by comparison of simulations and measurements for a single crystal and for the full array. Prospects for future development of the model are discussed.

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L. Riley, D. Weisshaar, H. Crawford, et. al.
Wed, 21 Apr 2021
32/72

Comments: 26 pages, 12 figures

Measurement of the $^{2}$H($p,γ$)$^{3}$He S-factor at 265-1094keV [CL]

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http://arxiv.org/abs/2104.06914


Recent astronomical data have provided the primordial deuterium abundance with percent precision. As a result, Big Bang nucleosynthesis may provide a constraint on the universal baryon to photon ratio that is as precise as, but independent from, analyses of the cosmic microwave background. However, such a constraint requires that the nuclear reaction rates governing the production and destruction of primordial deuterium are sufficiently well known. Here, a new measurement of the $^2$H($p,\gamma$)$^3$He cross section is reported. This nuclear reaction dominates the error on the predicted Big Bang deuterium abundance. A proton beam of 400-1650keV beam energy was incident on solid titanium deuteride targets, and the emitted $\gamma$-rays were detected in two high-purity germanium detectors at angles of 55$^\circ$ and 90$^\circ$, respectively. The deuterium content of the targets has been obtained in situ by the $^2$H($^3$He,$p$)$^4$He reaction and offline using the Elastic Recoil Detection method. The astrophysical S-factor has been determined at center of mass energies between 265 and 1094 keV, addressing the uppermost part of the relevant energy range for Big Bang nucleosynthesis and complementary to ongoing work at lower energies. The new data support a higher S-factor at Big Bang temperatures than previously assumed, reducing the predicted deuterium abundance.

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S. Turkat, S. Hammer, E. Masha, et. al.
Thu, 15 Apr 2021
22/59

Comments: 13 pages, 9 figures, 4 tables; to be published in Phys. Rev. C

Latin American HECAP Physics Briefing Book [CL]

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http://arxiv.org/abs/2104.06852


For the first time the scientific community in Latin America working at the forefront of research in high energy, cosmology and astroparticle physics (HECAP) have come together to discuss and provide scientific input towards the development of a regional strategy.
The present document, the Latin American HECAP Physics Briefing Book, is the result of this ambitious bottom-up effort. This report contains the work performed by the Preparatory Group to synthesize the main contributions and discussions for each of the topical working groups. This briefing book discusses the relevant emerging projects developing in the region and considers potentially impactful future initiatives and participation of the Latin American HECAP community in international flagship projects to provide the essential input for the creation of a long-term HECAP strategy in the region.

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H. Aihara, A. Aranda, R. Toro, et. al.
Thu, 15 Apr 2021
57/59

Comments: 89 pages

Proton-induced activation cross sections in the energy range below 1 GeV [HEAP]

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http://arxiv.org/abs/2103.01469


(Abridged) Modern studies and industrial applications related to the design, radiation protection, and reliability of nuclear facilities, medical applications, as well as space research and exploration are relying on extensive simulations and modeling. Computer codes realizing semi-classical and quantum molecular dynamics (QMD) approaches are often employed to make up for the lack of accelerator data on many nuclear reactions at intermediate and high energies (>10s of MeV/n) and are in high demand. This contribution focuses on the methodology of generating reliable proton-induced cross sections in the energy range below 1 GeV. We developed a problem-oriented computer framework based on MCNPX and CASCADE/INPE codes to calculate activation cross section data at intermediate and high energies. Goodness of the fits of nucleon-nucleus interaction models to the existing data is evaluated based on elaborated algorithms. The method is based on the analysis of a large set of data and calculated cross sections for different targets and residual nuclei in a wide range of proton energies using numerous criteria. In practice, this could be done by tuning the model parameters and algorithms to fit required experimental data subset, or through achieving unification and consistency of fundamental parameters for all considered reactions. The presented framework is pursuing the latter approach. We use proton-induced reactions on Si and Fe nuclei to illustrate the application of the developed multi-criteria algorithm, where we use all data below 1 GeV available from the EXFOR data library and the IAEA CRP “Benchmark of Spallation Models.” We show that the analysis of the predictive power of various intermediate and high-energy models based on the multi-criteria algorithm allows more sophisticated selection of appropriate models in a given energy range and residual nuclei domain.

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I. Moskalenko, A. Andrianov, A. Bytenko, et. al.
Wed, 3 Mar 21
51/82

Comments: A poster E1.16-0085-21 presented at an event E1.16 “Origin of Cosmic Rays,” 43th COSPAR Scientific Assembly (hybrid), 28 Jan – 4 Feb 2021, Sydney, Australia. For a full agenda of the event E1.16, see this https URL

Opportunities of OO and $p$O collisions at the LHC [CL]

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http://arxiv.org/abs/2103.01939


This is the summary document of the virtual workshop “Opportunities of OO and $p$O collisions at the LHC”, which took place Feb 4-10, 2021. We briefly review the presented perspectives on the physics opportunities of oxygen–oxygen and proton–oxygen collisions. The full workshop program and the recordings are available at cern.ch/OppOatLHC.

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J. Brewer, A. Mazeliauskas and W. Schee
Wed, 3 Mar 21
77/82

Comments: Workshop summary (see this http URL ), 6 pages, 9 figures

Supernova neutrino signals based on long-term axisymmetric simulations [HEAP]

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http://arxiv.org/abs/2102.11283


We study theoretical neutrino signals from core-collapse supernova (CCSN) computed using axisymmetric CCSN simulations that cover the post-bounce phase up to $\sim 4$~s. We provide basic quantities of the neutrino signals such as event rates, energy spectra, and cumulative number of events at some terrestrial neutrino detectors, and then we discuss some new features in the late phase that emerge in our models. Contrary to popular beliefs, neutrino emissions in the late phase are not always quiet, but rather have temporal fluctuations, the vigor of which hinges on the CCSN model and neutrino flavor. We find that the temporal variations are not primarily driven by proto-neutron star (PNS) convection, but by fallback accretion flows in explosion models. We assess the detectability of these temporal variations, and conclude that IceCube is the most promising detector with which to resolve them. We also update fitting formulae first proposed in our previous paper for which total neutrino energy (TONE) emitted at the CCSN source is estimated from the cumulative number of events at each detector. This will be very powerful in the data analysis of real observations, in particular for low-statistics data. As an interesting demonstration, we apply our fitting formulae to a real observation, that of SN 1987A at Kamiokande-II. The TONE is estimated as $\sim 2 \times 10^{53}$~erg. By combining the recent constraints on the equation-of-state, we further estimate the gravitational mass of PNS in the remnant of SN 1987A, which is $\sim 1.2~M_{\sun}$.

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H. Nagakura, A. Burrows and D. Vartanyan
Wed, 24 Feb 21
26/64

Comments: Submitted to MNRAS

A Review of Basic Energy Reconstruction Techniques in Liquid Xenon and Argon Detectors for Dark Matter and Neutrino Physics Using NEST [CL]

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http://arxiv.org/abs/2102.10209


Detectors based upon the noble elements, especially liquid xenon as well as liquid argon, as both single- and dual-phase types, require reconstruction of the energies of interacting particles, both in the field of direct detection of dark matter (WIMPs, axions, et al.) and in neutrino physics. Experimentalists, as well as theorists who reanalyze/reinterpret experimental data, have used a few different techniques over the past few decades. In this paper, we review techniques based on solely the primary scintillation channel, the ionization or secondary channel available at non-zero drift electric fields, and combined techniques that include a simple linear combination and weighted averages, with a brief discussion of the application of profile likelihood, maximum likelihood, and machine learning. Comparing results for electron recoils (beta and gamma interactions) and nuclear recoils (primarily from neutrons) from the NEST simulation to available data, we confirm that combining all available information generates higher-precision means, lower widths (energy resolution), and more symmetric shapes (approximately Gaussian) especially at keV-scale energies, with the symmetry even greater when thresholding is addressed. Near thresholds, bias from upward fluctuations matters. For MeV-GeV scales, if only one channel is utilized, an ionization-only-based energy scale outperforms scintillation; channel combination remains beneficial. We discuss what major collaborations use.

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M. Szydagis, G. Block, C. Farquhar, et. al.
Tue, 23 Feb 21
38/79

Comments: 44 Pages, 2 Tables, 11 Figures

Differential analysis of incompressibility in neutron-rich nuclei [CL]

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http://arxiv.org/abs/2102.10683


Both the incompressibility \Ka of a finite nucleus of mass A and that ($K_{\infty}$) of infinite nuclear matter are fundamentally important for many critical issues in nuclear physics and astrophysics. While some consensus has been reached about the $K_{\infty}$, accurate theoretical predictions and experimental extractions of $K_{\tau}$ characterizing the isospin dependence of \Ka have been very difficult. We propose a differential approach to extract the \Kt and \Ki independently from the \Ka data of any two nuclei in a given isotope chain. Applying this novel method to the \Ka data from giant monopole resonances in even-even Sn, Cd, Ca, Mo and Zr isotopes taken by U. Garg {\it et al.} at the Research Center for Nuclear Physics (RCNP), Osaka University, Japan, we find that the $^{106}$Cd-$^{116}$Cd and $^{112}$Sn-$^{124}$Sn pairs having the largest differences in isospin asymmetries in their respective isotope chains measured so far provide consistently the most accurate up-to-date \Kt value of $K_{\tau}=-616\pm 59$ MeV and $K_{\tau}=-623\pm 86$ MeV, respectively, largely independent of the remaining uncertainties of the surface and Coulomb terms in expanding the $K_{\rm A}$.

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B. Li and W. Xie
Tue, 23 Feb 21
55/79

Comments: 5 pages including 3 figures

Germanium response to sub-keV nuclear recoils: a multipronged experimental characterization [CL]

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http://arxiv.org/abs/2102.10089


Germanium is the detector material of choice in many rare-event searches looking for low-energy nuclear recoils induced by dark matter particles or neutrinos. We perform a systematic exploration of its quenching factor for sub-keV nuclear recoils, using multiple techniques: photo-neutron sources, recoils from gamma-emission following thermal neutron capture, and a monochromatic filtered neutron beam. Our results point to a marked deviation from the predictions of the Lindhard model in this mostly unexplored energy range. We comment on the compatibility of our data with low-energy processes such as the Migdal effect, and on the impact of our measurements on upcoming searches.

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J. Collar, A. Kavner and C. Lewis
Tue, 23 Feb 21
73/79

Comments: 10 pages, 10 figures

Astrophysical Constraints on the Symmetry Energy and the Neutron Skin of $^{208}$Pb with Minimal Modeling Assumptions [CL]

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http://arxiv.org/abs/2102.10074


The symmetry energy and its density dependence are crucial inputs for many nuclear physics and astrophysics applications, as they determine properties ranging from the neutron-skin thickness of nuclei to the crust thickness and the radius of neutron stars. Recently, PREX-II reported a value of $0.29\pm 0.07$ fm for the neutron-skin thickness of $^{208}$Pb, implying a slope parameter $L = 110\pm 37$ MeV, larger than most ranges obtained from microscopic calculations and other nuclear experiments. We use a nonparametric equation of state representation based on Gaussian processes to constrain the symmetry energy $S_0$, $L$, and $R_{\rm skin}^{^{208}\text{Pb}}$ directly from observations of neutron stars with minimal modeling assumptions. The resulting astrophysical constraints from heavy pulsar masses, LIGO/Virgo, and NICER clearly favor smaller values of the neutron skin and $L$, as well as negative symmetry incompressibilities. Combining astrophysical data with PREX-II and chiral effective field theory constraints yields $S_0 = 34^{+3}{-3}$ MeV, $L=58^{+19}{-19}$ MeV, and $R_{\rm skin}^{^{208}\text{Pb}} = 0.19^{+0.03}_{-0.04}$ fm.

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R. Essick, I. Tews, P. Landry, et. al.
Mon, 22 Feb 21
24/51

Comments: 7 pages, 4 figures, 1 table

Baryonic matter and the medium modification of the baryon masses [CL]

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http://arxiv.org/abs/2102.05292


We investigate the properties of baryonic matter within the framework of the in-medium modified chiral soliton model by taking into account the effects of surrounding baryonic environment on the properties of in-medium baryons. The internal parameters of the model are determined based on nuclear phenomenology at nonstrange sector and fitted by reproducing nuclear matter properties near the saturation point. We discuss the equations of state in different nuclear environments such as symmetric nuclear matter, neutron and strange matters. We show that the results for the equations of state are in good agreement with the phenomenology of nuclear matter. We also discuss how the SU(3) baryons masses undergo changes in these various types of nuclear matter.

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N. Ghim, G. Yang, H. Kim, et. al.
Thu, 11 Feb 21
53/62

Comments: 14 pages, 8 figures

Tasting Nuclear Pasta Made with Classical Molecular Dynamics Simulations [CL]

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http://arxiv.org/abs/2101.07843


Nuclear clusters or voids in the inner crust of neutron stars were predicted to have various shapes collectively nicknamed nuclear pasta. The recent review in Ref. \cite{Lopez1} by L\’opez, Dorso and Frank summarized their systematic investigations into properties especially the morphological and thermodynamical phase transitions of the nuclear pasta within a Classical Molecular Dynamics model, providing further stimuli to find more observational evidences of the predicted nuclear pasta in neutron stars.

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B. Li
Thu, 21 Jan 21
26/56

Comments: Invited View & Perspective

Analysis methods for the first KATRIN neutrino-mass measurement [CL]

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http://arxiv.org/abs/2101.05253


We report on the data set, data handling, and detailed analysis techniques of the first neutrino-mass measurement by the Karlsruhe Tritium Neutrino (KATRIN) experiment, which probes the absolute neutrino-mass scale via the $\beta$-decay kinematics of molecular tritium. The source is highly pure, cryogenic T$_2$ gas. The $\beta$ electrons are guided along magnetic field lines toward a high-resolution, integrating spectrometer for energy analysis. A silicon detector counts $\beta$ electrons above the energy threshold of the spectrometer, so that a scan of the thresholds produces a precise measurement of the high-energy spectral tail. After detailed theoretical studies, simulations, and commissioning measurements, extending from the molecular final-state distribution to inelastic scattering in the source to subtleties of the electromagnetic fields, our independent, blind analyses allow us to set an upper limit of 1.1 eV on the neutrino-mass scale at a 90\% confidence level. This first result, based on a few weeks of running at a reduced source intensity and dominated by statistical uncertainty, improves on prior limits by nearly a factor of two. This result establishes an analysis framework for future KATRIN measurements, and provides important input to both particle theory and cosmology.

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M. Aker, K. Altenmüller, A. Beglarian, et. al.
Thu, 14 Jan 21
41/79

Comments: 36 pages with 26 figures

Response of undoped cryogenic CsI to low-energy nuclear recoils [CL]

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http://arxiv.org/abs/2101.03264


The bright scintillation of pure CsI operated at liquid-nitrogen temperature makes of this material a promising dark matter and neutrino detector. We present the first measurement of its quenching factor for nuclear recoils. Our findings indicate it is indistinguishable from that for sodium-doped CsI at room temperature. Additional properties such as light yield, afterglow, scintillation decay properties for electron and nuclear recoils, and energy proportionality are studied over the \mbox{108-165 K} temperature range, confirming the vast potential of this medium for rare-event searches.

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C. Lewis and J. Collar
Wed, 13 Jan 21
68/70

Comments: N/A

Implications of PREX-II on the equation of state of neutron-rich matter [CL]

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http://arxiv.org/abs/2101.03193


Laboratory experiments sensitive to the equation of state of neutron rich matter in the vicinity of nuclear saturation density provide the first rung in a “density ladder” that connects terrestrial experiments to astronomical observations. In this context, the neutron skin thickness of 208Pb (Rskin) provides the most stringent laboratory constraint on the density dependence of the symmetry energy. In turn, the cleanest and most precise value of Rskin has been reported recently by the PREX collaboration. Exploiting the strong correlation between Rskin and the slope of the symmetry energy (L) we report a value of L=(109.56 +/- 36.41)MeV — that systematically overestimates current limits based on both theoretical approaches and experimental measurements. The impact of such a stiff symmetry energy on some critical neutron-star observables is also examined.

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B. Reed, F. Fattoyev, C. Horowitz, et. al.
Tue, 12 Jan 21
57/90

Comments: 5 pages, 4 figures, submitted to Physical Review Letters

The relevance of nuclear reactions for Standard Solar Models construction [SSA]

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http://arxiv.org/abs/2101.03077


The fundamental processes by which nuclear energy is generated in the Sun have been known for many years. However, continuous progress in areas such as neutrino experiments, stellar spectroscopy and helioseismic data and techniques requires ever more accurate and precise determination of nuclear reaction cross sections, a fundamental physical input for solar models. In this work, we review the current status of (standard) solar models and present a detailed discussion on the relevance of nuclear reactions for detailed predictions of solar properties. In addition, we also provide an analytical model that helps understanding the relation between nuclear cross sections, neutrino fluxes and the possibility they offer for determining physical characteristics of the solar interior. The latter is of particular relevance in the context of the conundrum posed by the solar composition, the solar abundance problem, and in the light of the first ever direct detection of solar CN neutrinos recently obtained by the Borexino collaboration. Finally, we present a short list of wishes about the precision with which nuclear reaction rates should be determined to allow for further progress in our understanding of the Sun.

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F. Villante and A. Serenelli
Mon, 11 Jan 21
49/65

Comments: 29 pages, Review article prepared for Research Topic “Nuclear reactions of astrophysical interest”, Front. Astron. Space Sci

Chiral Effective Field Theory and the High-Density Nuclear Equation of State [CL]

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http://arxiv.org/abs/2101.01709


Recent advances in neutron star observations have the potential to constrain the properties of strongly interacting matter at extreme densities and temperatures that are otherwise difficult to access through direct experimental investigation. At the same time, chiral effective field theory has developed into a powerful theoretical framework to study nuclear interactions and nuclear matter properties with quantified uncertainties in the regime of astrophysical interest for modeling neutron stars. In this article, we review recent developments in the chiral effective field theory approach to constructing microscopic nuclear forces and focus on many-body perturbation theory as a computationally efficient tool for calculating the structure, phases, and linear-response properties of hot and dense nuclear matter. We also demonstrate how effective field theory combined with Bayesian methods enables statistically meaningful comparisons between nuclear theory predictions, nuclear experiments, and observational constraints on the nuclear equation of state.

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C. Drischler, J. Holt and C. Wellenhofer
Wed, 6 Jan 21
3/82

Comments: 29 pages, 8 figures; invited review prepared for Annu. Rev. Nucl. Part. Sci. (2021)

Wavelength shifters for applications in liquid argon detectors [CL]

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http://arxiv.org/abs/2012.15626


Wavelength shifters and their applications for liquid argon detectors have been a subject of extensive R&D over the past decade. This work reviews the most recent results in this field. We compare the optical properties and usage details together with the associated challenges for various wavelength shifting solutions. We discuss the current status and potential future R&D directions for the main classes of wavelength shifters.

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M. Kuźniak and A. Szelc
Fri, 1 Jan 21
10/103

Comments: N/A

Wavelength shifters for applications in liquid argon detectors [CL]

Posted on by

http://arxiv.org/abs/2012.15626


Wavelength shifters and their applications for liquid argon detectors have been a subject of extensive R&D over the past decade. This work reviews the most recent results in this field. We compare the optical properties and usage details together with the associated challenges for various wavelength shifting solutions. We discuss the current status and potential future R&D directions for the main classes of wavelength shifters.

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M. Kuźniak and A. Szelc
Fri, 1 Jan 21
3/103

Comments: N/A

Imaging neutron capture cross sections: i-TED proof-of-concept and future prospects based on Machine-Learning techniques [CL]

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http://arxiv.org/abs/2012.10374


i-TED is an innovative detection system which exploits Compton imaging techniques to achieve a superior signal-to-background ratio in ($n,\gamma$) cross-section measurements using time-of-flight technique. This work presents the first experimental validation of the i-TED apparatus for high-resolution time-of-flight experiments and demonstrates for the first time the concept proposed for background rejection. To this aim both $^{197}$Au($n,\gamma$) and $^{56}$Fe($n, \gamma$) reactions were measured at CERN n_TOF using an i-TED demonstrator based on only three position-sensitive detectors. Two \cds detectors were also used to benchmark the performance of i-TED. The i-TED prototype built for this study shows a factor of $\sim$3 higher detection sensitivity than state-of-the-art \cds detectors in the $\sim$10~keV neutron energy range of astrophysical interest. This paper explores also the perspectives of further enhancement in performance attainable with the final i-TED array consisting of twenty position-sensitive detectors and new analysis methodologies based on Machine-Learning techniques.

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V. Babiano-Suárez, J. Lerendegui-Marco, J. Balibrea-Correa, et. al.
Mon, 21 Dec 20
44/75

Comments: 16 pages, 16 figures

A search for a cosmologically-relevant boson in muon decay [CL]

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http://arxiv.org/abs/2012.01504


Experiments looking for a lepton flavor-violating decay $\mu^{+}!!\rightarrow !e^{+} X^{0}$ are reviewed in light of present-day germanium detector technology, with an eye on scenarios where a long-lived, slow-moving massive boson $X^{0}$ might have a cosmological impact. A broad swath of interesting, unexplored parameter space very close to the kinematic limit of the decay is found to be within the reach of a new proposed search. A number of possible roles for $X^{0}$ in past and present epochs can be investigated.

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J. Collar
Fri, 4 Dec 20
14/77

Comments: 5 pages, 4 figures. Version submitted to Phys. Rev. D

Intrinsic Correlations Among Characteristics of Neutron-rich Matter Imposed by the Unbound Nature of Pure Neutron Matter [CL]

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http://arxiv.org/abs/2012.01549


The unbound nature of pure neutron matter (PNM) requires intrinsic correlations between the symmetric nuclear matter (SNM) EOS parameters (incompressibility $K_0$, skewness $J_0$ and kurtosis $I_0$) and those (slope $L$, curvature $K_{\rm{sym}}$ and skewness $J_{\rm{sym}}$) characterizing the symmetry energy independent of any nuclear many-body theory. We investigate these intrinsic correlations and their applications in better constraining the poorly known high-density behavior of nuclear symmetry energy. Several novel correlations connecting the characteristics of SNM EOS with those of nuclear symmetry energy are found. In particular, at the lowest-order of approximations, the bulk parts of the slope $L$, curvature $K_{\rm{sym}}$ and skewness $J_{\rm{sym}}$ of the symmetry energy are found to be $L\approx K_0/3, K_{\rm{sym}}\approx LJ_0/2K_0$ and $J_{\rm{sym}}\approx I_0L/3K_0$, respectively. High-order corrections to these simple relations can be written in terms of the small ratios of high-order EOS parameters. The resulting intrinsic correlations among some of the EOS parameters reproduce very nicely their relations predicted by various microscopic nuclear many-body theories and phenomenological models constrained by available data of terrestrial experiments and astrophysical observations in the literature. The unbound nature of PNM is fundamental and the required intrinsic correlations among the EOS parameters characterizing both the SNM EOS and symmetry energy are universal. These intrinsic correlations provide a novel and model-independent tool not only for consistency checks but also for investigating the poorly known high-density properties of neutron-rich matter by using those with smaller uncertainties.

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B. Cai and B. Li
Fri, 4 Dec 20
71/77

Comments: 9 pages with 5 figures

Sub-threshold states in $^{19}$Ne relevant to $^{18}$F(p,$α$)$^{15}$O [CL]

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http://arxiv.org/abs/2011.13222


Classical novae result from thermonuclear explosions producing several $\gamma$-ray emitters which are prime targets for satellites observing in the MeV range. The early 511 keV gamma-ray emission depends critically on the $^{18}$F(p,$\alpha$)$^{15}$O reaction rate which, despite many experimental and theoretical efforts, still remains uncertain. One of the main uncertainties in the $^{18}$F(p,$\alpha$)$^{15}$O reaction rate is the contribution in the Gamow window of interference between sub-threshold $^{19}$Ne states and known broad states at higher energies. Therefore the goal of this work is to clarify the existence and the nature of these sub-threshold states. States in the $^{19}$Ne compound nucleus were studied at the Tandem-ALTO facility using the $^{19}$F($^3$He,t)$^{19}$Ne charge exchange reaction. Tritons were detected with an Enge Split-pole spectrometer while decaying protons or $\alpha$-particles from unbound $^{19}$Ne states were collected, in coincidence, with a double-sided silicon strip detector array. Angular correlations were extracted and constraints on the spin and parity of decaying states established. The coincidence yield at $E_x$ = 6.29 MeV was observed to be high spin, supporting the conclusion that it is indeed a doublet consisting of high spin and low spin components. Evidence for a broad, low spin state was observed around 6 MeV. Branching ratios were extracted for several states above the proton threshold and were found to be consistent with the literature. R-matrix calculations show the relative contribution of sub-threshold states to the astrophysically important energy region above the proton threshold. The levels schemes of $^{19}$Ne and $^{19}$F are still not sufficiently well known and further studies of the analogue assignments are needed. The tentative broad state at 6 MeV may only play a role if the reduced proton width is large.

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J. Riley, A. Laird, N. Séréville, et. al.
Mon, 30 Nov 20
9/117

Comments: N/A

The Impact of New d(p,γ)He3 Rates on Big Bang Nucleosynthesis [CEA]

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http://arxiv.org/abs/2011.13874


We consider the effect on Big Bang Nucleosynthesis (BBN) of new measurements of the $d(p,\gamma){}^3$He cross section by the LUNA Collaboration. These have an important effect on the primordial abundance of D/H which is also sensitive to the baryon density at the time of BBN. We have re-evaluated the thermal rate for this reaction, using a world average of cross section data, which we describe with model-independent polynomials; our results are in good agreement with a similar analysis by LUNA. We then perform a full likelihood analysis combining BBN and Planck cosmic microwave background (CMB) likelihood chains using the new rate combined with previous measurements and compare with the results using previous rates. Concordance between BBN and CMB measurements of the anisotropy spectrum using the old rates was excellent. The predicted deuterium abundance at the Planck value of the baryon density was $({\rm D/H}){\rm BBN+CMB}^{\rm old} = (2.57 \pm 0.13) \times 10^{-5}$ which can be compared with the value determined from quasar absorption systems $({\rm D/H}){\rm obs} = (2.55 \pm 0.03) \times 10^{-5} $. Using the new rates we find $({\rm D/H}){\rm BBN+CMB} = (2.51 \pm 0.11) \times 10^{-5}$. We thus find consistency among BBN theory, deuterium and ${}^4$He observations, and the CMB, when using reaction rates fit in our data-driven approach. We also find that the new reaction data tightens the constraints on the number of relativistic degrees of freedom during BBN, giving the effective number of light neutrino species $N\nu = 2.880 \pm 0.144$ in good agreement with the Standard Model of particle physics. Finally, we note that the observed deuterium abundance continues to be more precise than the BBN+CMB prediction, whose error budget is now dominated by $d(d,n){}^3$He and $d(d,p){}^{3}{\rm H}$.

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T. Yeh, K. Olive and B. Fields
Mon, 30 Nov 20
58/117

Comments: 28 pages, 12 figures. Comments welcome

QCD equations of state and speed of sound in neutron stars [CL]

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http://arxiv.org/abs/2011.10940


Neutron stars are cosmic laboratories to study dense matter in Quantum Chromodynamics (QCD). The observable mass-radius relations of neutron stars are determined by QCD equations of state, and can reflect the properties of QCD phase transitions. In the last decade there have been historical discoveries in neutron stars, the discoveries of two-solar mass neutron stars and neutron star merger events, which have imposed tight constraints on equations of state. While a number of equations of state are constructed to satisfy these constraints, a theoretical challenge is how to reconcile those constructions with the microphysics expected from the hadron physics and in-medium calculations. In this short article we briefly go over recent observations and discuss their implications for dense QCD matter, referring to QCD constraints in the low and high density limits, QCD-like theories, and lattice QCD results for baryon-baryon interactions.

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T. Kojo
Tue, 24 Nov 2020
77/83

Comments: 9 pages, 2 figures, a review contributed to the AAPPS Bulletin

The origin of the elements and other implications of gravitational wave detection for nuclear physics [CL]

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http://arxiv.org/abs/2011.08645


The neutron-star collision revealed by the event GW170817 gave us a first glimpse of a possible birthplace of most of our heavy elements. The multi-messenger nature of this historical event combined gravitational waves, a gamma-ray burst and optical astronomy of a “kilonova”, bringing the first observations of rapid neutron capture (r process) nucleosynthesis after 60 years of speculation. Modeling the r process requires a prodigious amount of nuclear-physics ingredients: practically all the quantum state and interaction properties of virtually all neutron-rich nuclides, many of which may never be produced in the laboratory! Another essential contribution of nuclear physics to neutron stars (and their eventual coalescence) is the equation of state (EoS) that defines their structure and composition. The EoS, combined with the knowledge of nuclear binding energies, determines the elemental profile of the outer crust of a neutron star and the relationship between its radius and mass. In addition, the EoS determines the form of the gravitational wave signal. This article combines a tutorial presentation and bibliography with recent results that link nuclear mass spectrometry to gravitational waves via neutron stars.

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D. Lunney
Wed, 18 Nov 20
75/79

Comments: Invited tutorial/review paper for a Special Issue of 4Open-Sciences (EDP) on “Gravitational waves and the advent of multi-messenger astronomy,” following a minisymposium bearing the same title, held during the 2019 National Conference of the SFP (Soci\’et\’e Fran\c{c}aise de Physique) in Nantes, France (14 pages, 3 figures)

Calculable microscopic theory for $^{12}$C($α, γ$)$^{16}$O cross section near Gamow window [CL]

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http://arxiv.org/abs/2011.06701


$^{12}$C$(\alpha, \gamma)^{16}$O radiative-capture process is a key reaction to produce the element of oxygen in stars. Measuring the cross section near the Gamow window is extremely hard because it is too small. To make a theoretical contribution towards resolving the long-standing problem, I present a microscopic formulation that aims at providing all materials needed to calculate the cross section. The states of $^{12}$C and $^{16}$O relevant to the reaction are respectively described with fully microscopic 3 $\alpha$-particle and 4 $\alpha$-particle configurations, in which the relative motion among the $\alpha$ particles is expanded in terms of correlated Gaussian basis functions. The configuration space has the advantage of being able to well describe the reduced $\alpha$-width amplitudes of the states of $^{16}$O. Both electric dipole and electric quadrupole transitions are responsible for the radiative-capture process. The $\alpha$ particle is described with a $(0s)^4$ configuration admixed with a small amount of an isospin $T=1$ impurity component, which is crucially important to account for the isovector electric dipole transition. The isoscalar electric dipole operators are also taken into account up to the first order beyond the long-wavelength approximation. All the necessary ingredients are provided to make the paper self-contained and ready for numerical computations.

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Y. Suzuki
Mon, 16 Nov 20
29/57

Comments: 24 pages, accepted for publication in Few-Body Systems

Non-thermal neutrinos created by shock acceleration in successful and failed core-collapse supernova [HEAP]

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http://arxiv.org/abs/2010.15136


We present a comprehensive study of neutrino shock acceleration in core-collapse supernova (CCSN). The leading players are heavy leptonic neutrinos, $\nu_{\mu}$ and $\nu_{\tau}$; the former and latter potentially gain the energy up to $\sim 100$ MeV and $\sim 200$ MeV, respectively, through the shock acceleration. Demonstrating the neutrino shock acceleration by Monte Carlo neutrino transport, we make a statement that it commonly occurs in the early post bounce phase ($\lesssim 50$ ms after bounce) for all massive stellar collapse experiencing nuclear bounce and would reoccur in the late phase ($\gtrsim 100$ ms) for failed CCSNe. This opens up a new possibility to detect high energy neutrinos by terrestrial detectors from Galactic CCSNe; hence, we estimate the event counts for Hyper(Super)-Kamiokande, DUNE, and JUNO. We find that the event count with the energy of $\gtrsim 80$ MeV is a few orders of magnitude higher than that of the thermal neutrinos regardless of the detectors, and muon production may also happen in these detectors by $\nu_{\mu}$ with the energy of $\gtrsim 100$ MeV. The neutrino signals provide a precious information on deciphering the inner dynamics of CCSN and placing a constraint on the physics of neutrino oscillation; indeed, the detection of the high energy neutrinos through charged current reaction channels will be a smoking gun evidence of neutrino flavor conversion.

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H. Nagakura and K. Hotokezaka
Fri, 30 Oct 20
56/74

Comments: Submitted to MNRAS

Annual variations of the $^{214}$Po, $^{213}$Po and $^{212}$Po half-life values [CL]

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http://arxiv.org/abs/2010.08283


Results of a comparative analysis of the $^{214}$Po ($T_{1/2}= 163.47\pm0.03$ $\mu$s), $^{213}$Po ($T_{1/2}=3.705 \pm 0.001$ $\mu$s) and $^{212}$Po ($T_{1/2}=294.09\pm0.07$ ns) half-life annular variation parameters are presented. It is shown that two independent sequential sets of the $^{214}$Po $\tau$-values $(\tau\equiv T_{1/2})$ obtained in the spaced laboratories can be described by sinusoidal functions. The sinusoid curve with amplitude $A=(5.0 \pm1.5) \cdot 10^{-4}$, period $\omega=(365\pm 8)$ days, and phase $\phi=(170 \pm 7)$ days approximates the set of $^{214}$Po $\tau$ values obtained at BNO INR RAS during the $\sim$973 days starting on January 4, 2012. The function approximates a set of $\tau$-values with a time duration of $\sim1460$ days obtained at the KhNU has an amplitude $A=(4.9\pm1.8)\cdot10^{-4}$, a period $\omega= (377\pm13)$ days and a phase $\phi=(77\pm10)$ days. The $^{213}$Po $\tau$-value set with a time duration of $\sim1700$ days can be described by a sinusoidal function with an amplitude $A=(3.9\pm1.2)\cdot10^{-4}$, a period $\omega= (370\pm13)$ days and a phase $\phi=(130\pm9)$ days. The $^{212}$Po $\tau$-value set with a time duration of $\sim670$ days can be described by a sinusoidal function with an amplitude $A=(7.5\pm1.6)\cdot10^{-4}$, a period $\omega= (375\pm13)$ days and a phase $\phi=(40\pm10)$ days.

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E. E.N.Alexeev, A. A.M.Gangapshev, Y. Yu.M.Gavrilyuk, et. al.
Mon, 19 Oct 20
24/44

Comments: 6 pages, 5 figures, Prepared for the proceedings of The 5th International Conference on Particle Physics and Astrophysics (ICPPA-2020)

Assessing the impact of valence sd neutrons and protons on fusion [CL]

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http://arxiv.org/abs/2010.05720


Experimental above-barrier fusion cross-sections for 17F + 12C are compared to the fusion excitation functions for 16,18O, 19F, and 20Ne ions on a carbon target. In comparing the different systems both the differing static size of the incident ions and changes in fusion barrier are accounted for by examining the reduced fusion cross-section. Remaining trends of the fusion cross-section above the barrier which reflect the sensitive interplay of the sd protons and neutrons are observed. The experimental data are also compared to both a widely-used analytical model of near-barrier fusion, as well as a time-dependent Hartree-Fock model. Both models fail to describe the trends observed.

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V. Singh, J. Vadas, T. Steinbach, et. al.
Tue, 13 Oct 20
90/97

Comments: 6 pages, 6 figures

Cosmogenic activation in double beta decay experiments [CL]

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http://arxiv.org/abs/2010.02381


Double beta decay is a very rare nuclear process and, therefore, experiments intended to detect it must be operated deep underground and in ultra-low background conditions. Long-lived radioisotopes produced by the previous exposure of materials to cosmic rays on the Earth’s surface or even underground can become problematic for the required sensitivity. Here, the studies developed to quantify and reduce the activation yields in detectors and materials used in the set-up of these experiments will be reviewed, considering target materials like germanium, tellurium and xenon together with other ones commonly used like copper, lead, stainless steel or argon. Calculations following very different approaches and measurements from irradiation experiments using beams or directly cosmic rays will be considered for relevant radioisotopes. The effect of cosmogenic activation in present and future double beta decay projects based on different types of detectors will be analyzed too.

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S. Cebrian
Wed, 7 Oct 20
64/76

Comments: N/A

Spin-polarized $β$-stable neutron star matter: the nuclear symmetry energy and GW170817 constraint [CL]

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http://arxiv.org/abs/2010.00869


Magnetic field of rotating pulsar might be so strong that the equation of state (EOS) of neutron star (NS) matter is significantly affected by the spin polarization of baryons. In the present work, the EOS of the spin-polarized nuclear matter is investigated in the nonrelativistic Hartree-Fock formalism, using a realistic density dependent nucleon-nucleon interaction with its spin and spin-isospin dependence accurately adjusted to the Brueckner-Hartree-Fock results for the spin-polarized nuclear matter. The nuclear symmetry energy and proton fraction are found to increase significantly with the increasing spin polarization of baryons, leading to a larger probability of the direct Urca process in the cooling of magnetar. The EOS of the $\beta$-stable np$e\mu$ matter obtained at different spin polarizations of baryons is used as the input for the Tolman-Oppenheimer-Volkov equations to determine the hydrostatic configuration of NS. Based on the GW170817 constraint on the radius $R_{1.4}$ of NS with $M\approx 1.4_\odot$, our mean-field results show that up to $60~\%$ of baryons in the NS merger might be spin-polarized. This result supports the magnetar origin of the blue kilonova ejecta of GW170817 suggested by Metzger et al., and the spin polarization of baryons needs, therefore, to be properly treated in the many-body calculation of the EOS of NS matter before comparing the calculated NS mass and radius with those constrained by the multi-messenger GW170817 observation.

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N. Tan, D. Khoa and D. Loan
Mon, 5 Oct 20
16/61

Comments: Accepted for publication in Physical Review C

Bayesian inference of dense matter EOS encapsulating a first-order hadron-quark phase transition from observables of canonical neutron stars [CL]

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http://arxiv.org/abs/2009.13653


[Purpose:] We infer the posterior probability distribution functions (PDFs) and correlations of nine parameters characterizing the EOS of dense neutron-rich matter encapsulating a first-order hadron-quark phase transition from the radius data of canonical NSs reported by LIGO/VIRGO, NICER and Chandra Collaborations. We also infer the quark matter (QM) mass fraction and its radius in a 1.4 M${\odot}$ NS and predict their values in more massive NSs. [Method:] Meta-modelings are used to generate both hadronic and QM EOSs in the Markov-Chain Monte Carlo sampling process within the Bayesian statistical framework. An explicitly isospin-dependent parametric EOS for the $npe\mu$ matter in NSs at $\beta$ equilibrium is connected through the Maxwell construction to the QM EOS described by the constant speed of sound (CSS) model of Alford, Han and Prakash. [Results:] (1) The most probable values of the hadron-quark transition density $\rho_t/\rho_0$ and the relative energy density jump there $\De\ep/\ep_t$ are $\rho_t/\rho_0=1.6^{+1.2}{-0.4}$ and $\De\ep/\ep_t=0.4^{+0.20}{-0.15}$ at 68\% confidence level, respectively. The corresponding probability distribution of QM fraction in a 1.4 M${\odot}$ NS peaks around 0.9 in a 10 km sphere. Strongly correlated to the PDFs of $\rho_t$ and $\De\ep/\ep_t$, the PDF of the QM speed of sound squared $\cQMsq/c^2$ peaks at $0.95^{+0.05}_{-0.35}$, and the total probability of being less than 1/3 is very small. (2) The correlations between PDFs of hadronic and QM EOS parameters are very weak. [Conclusions:] The available astrophysical data considered together with all known EOS constraints from theories and terrestrial nuclear experiments prefer the formation of a large volume of QM even in canonical NSs.

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W. Xie and B. Li
Wed, 30 Sep 2020
62/86

Comments: 8 pages with 4 figures

The radiative width of the Hoyle state from $γ$-ray spectroscopy [CL]

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http://arxiv.org/abs/2009.10915


The cascading 3.21 MeV and 4.44 MeV electric quadrupole transitions have been observed from the Hoyle state at 7.65 MeV excitation energy in $^{12}$C, excited by the $^{12}$C(p,p$^{\prime}$) reaction at 10.7 MeV proton energy. From the proton-$\gamma$-$\gamma$ triple coincidence data, a value of ${\Gamma_{\rm rad}}/{\Gamma}=6.2(6) \times 10^{-4}$ was obtained for the radiative branching ratio. Using our results, together with ${\Gamma_{\pi}^{E0}}/{\Gamma}$ from Eriksen et al., Phys. Rev. C 102, 024320 and the currently adopted $\Gamma_{\pi}(E0)$ values, the radiative width of the Hoyle state is determined as $\Gamma_{\rm rad}=5.1(6) \times 10^{-3}$ eV. This value is about 34% higher than the currently adopted value and will impact on models of stellar evolution and nucleosynthesis.

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T. KibAdi, B. Alshahrani, A. Stuchbery, et. al.
Thu, 24 Sep 2020
15/61

Comments: 6 pages, 6 figures

Neutral tritium gas reduction in the KATRIN differential pumping sections [CL]

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http://arxiv.org/abs/2009.10403


The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to measure the effective electron anti-neutrino mass with an unprecedented sensitivity of $0.2\,\mathrm{eV}/\mathrm{c}^2$, using $\beta$-electrons from tritium decay. The electrons are guided magnetically by a system of superconducting magnets through a vacuum beamline from the windowless gaseous tritium source through differential and cryogenic pumping sections to a high resolution spectrometer and a segmented silicon pin detector. At the same time tritium gas has to be prevented from entering the spectrometer. Therefore, the pumping sections have to reduce the tritium flow by more than 14 orders of magnitude. This paper describes the measurement of the reduction factor of the differential pumping section performed with high purity tritium gas during the first measurement campaigns of the KATRIN experiment. The reduction factor results are compared with previously performed simulations, as well as the stringent requirements of the KATRIN experiment.

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A. Marsteller, B. Bornschein, L. Bornschein, et. al.
Wed, 23 Sep 20
-1737/86

Comments: 19 pages, 4 figures, submitted to Vacuum

New equations of state constrained by nuclear physics, observations, and high-density QCD calculations [CL]

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http://arxiv.org/abs/2009.08885


We present new equations of state for applications in core-collapse supernova and neutron star merger simulations. We start by introducing an effective mass parametrization that is fit to recent microscopic calculations up to twice saturation density. This is important to capture the predicted thermal effects, which have been shown to determine the proto-neutron star contraction in supernova simulations. The parameter range of the energy-density functional underlying the equation of state is constrained by chiral effective field theory results at nuclear densities as well as by functional renormalization group computations at high densities based on QCD. We further implement observational constraints from measurements of heavy neutron stars, the gravitational wave signal of GW170817, and from the recent NICER results. Finally, we study the resulting allowed ranges for the equation of state and for properties of neutron stars, including the predicted ranges for the neutron star radius and maximum mass.

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S. Huth, C. Wellenhofer and A. Schwenk
Mon, 21 Sep 20
-1685/60

Comments: 20 pages, 18 figures

Supernova Neutrino Burst Detection with the Deep Underground Neutrino Experiment [CL]

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http://arxiv.org/abs/2008.06647


The Deep Underground Neutrino Experiment (DUNE), a 40-kton underground liquid argon time projection chamber experiment, will be sensitive to the electron-neutrino flavor component of the burst of neutrinos expected from the next Galactic core-collapse supernova. Such an observation will bring unique insight into the astrophysics of core collapse as well as into the properties of neutrinos. The general capabilities of DUNE for neutrino detection in the relevant few- to few-tens-of-MeV neutrino energy range will be described. As an example, DUNE’s ability to constrain the $\nu_e$ spectral parameters of the neutrino burst will be considered.

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B. Abi, R. Acciarri, M. Acero, et. al.
Wed, 19 Aug 20
-1056/52

Comments: 29 pages, 17 figures; paper based on DUNE Technical Design Report

Search for event bursts in XMASS-I associated with gravitational-wave events [HEAP]

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http://arxiv.org/abs/2007.16046


We performed a search for event bursts in the XMASS-I detector associated with 11 gravitational-wave events detected during LIGO/Virgo’s O1 and O2 periods. Simple and loose cuts were applied to the data collected in the full 832 kg xenon volume around the detection time of each gravitational-wave event. The data were divided into four energy regions ranging from keV to MeV. Without assuming any particular burst models, we looked for event bursts in sliding windows with various time width from 0.02 to 10 s. The search was conducted in a time window between $-$400 and $+$10,000 s from each gravitational-wave event. For the binary neutron star merger GW170817, no significant event burst was observed in the XMASS-I detector and we set 90% confidence level upper limits on neutrino fluence for the sum of all the neutrino flavors via coherent elastic neutrino-nucleus scattering. The obtained upper limit was (1.3-2.1)$\times 10^{11}$ cm$^{-2}$ under the assumption of a Fermi-Dirac spectrum with average neutrino energy of 20 MeV. The neutrino fluence limits for mono-energetic neutrinos in the energy range between 14 and 100 MeV were also calculated. Among the other 10 gravitational wave events detected as the binary black hole mergers, a burst candidate with a global significance of 3.4$\sigma$ was found at 1801.95 s from GW151012. However, no significant deviation from the background in the reconstructed energy and position distributions was found.

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X. Collaboration, K. Abe, K. Hiraide, et. al.
Mon, 3 Aug 20
-675/58

Comments: 7 pages, 9 figures

Cosmogenic activation of silicon [CL]

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http://arxiv.org/abs/2007.10584


The production of $^{3}$H, $^{7}$Be, and $^{22}$Na by interactions of cosmic-ray particles with silicon can produce radioactive backgrounds in detectors used to search for rare events. Through controlled irradiation of silicon CCDs and wafers with a neutron beam that mimics the cosmic-ray neutron spectrum, followed by direct counting, we determined that the production rate from cosmic-ray neutrons at sea level is ($112 \pm 24$) atoms/(kg day) for $^{3}$H, ($8.1 \pm 1.9 $) atoms/(kg day) for $^{7}$Be, and ($43.0 \pm 7.1 $) atoms/(kg day) for $^{22}$Na. Complementing these results with the current best estimates of activation cross sections for cosmic-ray particles other than neutrons, we obtain a total sea-level cosmic-ray production rate of ($124 \pm 24$) atoms/(kg day) for $^{3}$H, ($9.4 \pm 2.0 $) atoms/(kg day) for $^{7}$Be, and ($49.6 \pm 7.3 $) atoms/(kg day) for $^{22}$Na. These measurements will help constrain background estimates and determine the maximum time that silicon-based detectors can remain unshielded during detector fabrication before cosmogenic backgrounds impact the sensitivity of next-generation rare-event searches.

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R. Saldanha, R. Thomas, R. Tsang, et. al.
Thu, 23 Jul 20
-458/83

Comments: 21 pages, 16 figures, 10 tables

Charged-particle branching ratios above the neutron threshold in $^{19}$F: constraining $^{15}$N production in core-collapse supernovae [CL]

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http://arxiv.org/abs/2007.03965


Spatially-correlated overabundances of $^{15}$N and $^{18}$O observed in some low-density graphite meteoritic grains have been connected to nucleosynthesis taking place in the helium-burning shell during core-collapse supernovae. Two of the reactions which have been identified as important to the final abundances of $^{15}$N and $^{18}$O are $^{18}$F($n,\alpha$)$^{15}$N and $^{18}$F($n,p$)$^{18}$O. The relative strengths of the $^{18}$F($n,\alpha$)$^{15}$N and $^{18}$F($n,p$)$^{18}$O reactions depend on the relative $\alpha_0$ and $p_0$ decays from states above the neutron threshold in $^{19}$F in addition to other properties. Experimental data on the charged-particle decays from these highly excited states are lacking or inconsistent. Two experiments were performed using proton inelastic scattering from LiF targets and magnetic spectrographs. The first experiment used the high-resolution Q3D spectrograph at Munich to constrain properties of levels in $^{19}$F. A second experiment using the Orsay Split-Pole spectrograph and an array of silicon detectors was performed in order to measure the charged-particle decays of neutron-unbound levels in $^{19}$F. A number of levels in $^{19}$F have been identified along with their corresponding charged-particle decays. The first state above the neutron threshold which has an observed proton-decay branch to the ground state of $^{18}$O lies 68 keV above the neutron threshold while the $\alpha$-particle decays from the neutron-unbound levels are generally observed to be much stronger than the proton decays. Neutron-unbound levels in $^{19}$F are observed to decay predominantly by $\alpha$-particle emission, supporting the role of $^{18}$F($n,\alpha$)$^{15}$N in the production of $^{15}$N in the helium-burning shell of supernovae. Improved resonant-scattering reaction data are required in order to be able to determine the reaction rates accurately.

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P. Adsley, F. Hammache, N. Séréville, et. al.
Thu, 9 Jul 20
-23/70

Comments: 13 pages, 5 figures

GW190814: Impact of a 2.6 solar mass neutron star on nucleonic equations of state [CL]

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http://arxiv.org/abs/2007.03799


Is the secondary component of GW190814 the lightest black hole or the heaviest neutron star ever discovered in a double compact-object system [R. Abbott et al., ApJ Lett., 896, L44 (2020)]? This is the central question animating this letter. Covariant density functional theory provides a unique framework to investigate both the properties of finite nuclei and neutron stars, while enforcing causality at all densities. By tuning existing energy density functionals we were able to: (a) account for a 2.6 Msun neutron star, (b) satisfy the original constraint on the tidal deformability of a 1.4 Msun neutron star, and (c) reproduce ground-state properties of finite nuclei. Yet, for the class of models explored in this work, we find that the stiffening of the equation of state required to support super-massive neutron stars is inconsistent with either constraints obtained from energetic heavy-ion collisions or from the low deformability of medium-mass stars. Thus, we speculate that the maximum neutron star mass can not be significantly higher than the existing observational limit and that the 2.6 Msun compact object is likely to be the lightest black hole ever discovered.

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F. Fattoyev, C. Horowitz, J. Piekarewicz, et. al.
Thu, 9 Jul 20
13/70

Comments: 6 pages and 3 figures

Technique for Surface Background Rejection in Liquid Argon Dark Matter Detectors using Layered Wavelength-Shifting and Scintillating Thin Films [CL]

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http://arxiv.org/abs/1903.00257


A technique using layered wavelength shifting, scintillating and non-scintillating films is presented to achieve discrimination of surface $\alpha$ events from low-energy nuclear recoils in liquid argon detectors. A discrimination power greater than $10^{8}$, similar to the discrimination possible for electronic recoils in argon, can be achieved by adding a 50 micron layer of scintillator with a suitably slow decay time, approximately 300 ns or greater, to a wavelength-shifter coated surface. The technique would allow suppression of surface $\alpha$ events in a very large next-generation argon dark matter experiment (with hundreds of square meters of surface area) without the requirement for position reconstruction, thus allowing utilization of more of the instrumented mass in the dark matter search. The technique could also be used to suppress surface backgrounds in compact argon detectors of low-energy nuclear recoils, for example in measurements of coherent neutrino-nucleus scattering or for sensitive measurements of neutron fluxes.

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M. Boulay and M. Kuźniak
Wed, 8 Jul 20
64/77

Comments: 7 pages, 6 figures

Excess of soft dielectrons and photons [CL]

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http://arxiv.org/abs/2006.12033


Spectra of unbound electron-positron pairs (dielectrons, in brief) and photons from decays of parapositronia produced in ultraperipheral collisions of electrically charged objects are calculated. Their shapes at energies of the collider NICA are demonstrated. The soft dielectrons and photons are abundantly produced. The relevance of these processes to the astrophysical problem of cooling electron-positron pairs and the intense emission of 511 keV photons from the Galactic center is discussed.

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I. Dremin
Thu, 25 Jun 20
70/78

Comments: 10 pages, 2 Figures

The modified astrophysical S-factor of the ${}^{12}$C+${}^{12}$C fusion reaction at sub-barrier energies [CL]

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http://arxiv.org/abs/2006.06305


The $^{12}$C+$^{12}$C fusion reaction plays a crucial role in stellar evolution and explosions. Its open reaction channels mainly include $\alpha$, $p$, $n$, and ${}^{8}$Be. Despite more than a half century of efforts, large discrepancies remain among the experimental data measured using various techniques. In this work, we analyze the existing data using the statistical model. Our calculation shows: 1) the relative systematic uncertainties of the predicted branching ratios get smaller as the predicted ratios increase; 2) the total modified astrophysical S-factors (S$^$ factors) of the $p$ and $\alpha$ channels can each be obtained by summing the S$^$ factors of their corresponding ground-state transitions and the characteristic $\gamma$ rays while taking into account the contributions of the missing channels to the latter. After applying corrections based on branching ratios predicted by the statistical model, an agreement is achieved among the different data sets at ${E}_{cm}>$4 MeV, while some discrepancies remain at lower energies suggesting the need for better measurements in the near future. We find that the recent S$^*$ factor obtained from an indirect measurement is inconsistent with the direct measurement at energies below 2.6 MeV. We recommend upper and lower limits for the ${}^{12}$C+${}^{12}$C S$^*$ factor based on the existing models. A new $^{12}$C+$^{12}$C reaction rate is also recommended.

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Y. Li, X. Fang, B. Bucher, et. al.
Fri, 12 Jun 20
56/69

Comments: N/A

Re-evaluation of the $^{22}$Ne($α,γ$)$^{26}$Mg and $^{22}$Ne($α,n$)$^{25}$Mg reaction rates [CL]

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http://arxiv.org/abs/2005.14482


The competing $^{22}$Ne($\alpha,\gamma$)$^{26}$Mg and $^{22}$Ne($\alpha,n$)$^{25}$Mg reactions control the production of neutrons for the weak $s$-process in massive and AGB stars. In both systems, the ratio between the corresponding reaction rates strongly impacts the total neutron budget and strongly influences the final nucleosynthesis. The $^{22}$Ne($\alpha,\gamma$)$^{26}$Mg and $^{22}$Ne($\alpha,n$)$^{25}$Mg reaction rates was re-evaluated by using newly available information on $^{26}$Mg given by various recent experimental studies. Evaluations of The evaluated $^{22}$Ne($\alpha,\gamma$)$^{26}$Mg reaction rate remains substantially similar to that of Longland {\it et al.} but, including recent results from Texas A\&M, the $^{22}$Ne($\alpha,n$)$^{25}$Mg reaction rate is lower at a range of astrophysically important temperatures. Stellar models computed with NEWTON and MESA predict decreased production of the weak branch $s$-process due to the decreased efficiency of $^{22}$Ne as a neutron source. Using the new reaction rates in the MESA model results in $^{96}$Zr/$^{94}$Zr and $^{135}$Ba/$^{136}$Ba ratios in much better agreement with the measured ratios from presolar SiC grains.

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P. Adsley, U. Battino, A. Best, et. al.
Mon, 1 Jun 20
33/50

Comments: 23 pages, 15 figures

Sensitivity of ${^{44}}$Ti and ${^{56}}$Ni production in CCSN shock-driven nucleosynthesis to reaction rates [HEAP]

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http://arxiv.org/abs/2005.14702


Recent observational advances have enabled high resolution mapping of ${^{44}}$Ti in core-collapse supernova (CCSN) remnants. Comparisons between observations and models provide stringent constraints on the CCSN mechanism. However, past work has identified several uncertain nuclear reaction rates that influence ${^{44}}$Ti and ${^{56}}$Ni production in post-processing model calculations. We evolved one dimensional models of $15~M_{\odot}$, $18~M_{\odot}$, $22~M_{\odot}$ and $25~M_{\odot}$ stars from zero-age main sequence through CCSN using {\tt MESA} (Modules for Experiments in Stellar Astrophysics) and investigated the previously identified reaction rate sensitivities of ${^{44}}$Ti and ${^{56}}$Ni production. We tested the robustness of our results by making various assumptions about the CCSN explosion energy and mass-cut. We found a number of reactions that have a significant impact on the nucleosynthesis of ${^{44}}$Ti and ${^{56}}$Ni, particularly for lower progenitor masses. Notably, the reaction rates $^{13}{\rm N}(\alpha,p)^{16}{\rm O}$, $^{17}{\rm F}(\alpha,p)^{20}{\rm Ne}$, $^{52}{\rm Fe}(\alpha,p)^{55}{\rm Co}$, $^{56}{\rm Ni}(\alpha,p)^{59}{\rm Cu}$, $^{57}{\rm Ni}(n,p)^{57}{\rm Co}$, $^{56}{\rm Co}(p,n)^{56}{\rm Ni}$, $^{39}{\rm K}(p,\gamma)^{40}{\rm Ca}$, $^{47}{\rm V}(p,\gamma)^{48}{\rm Cr}$, $^{52}{\rm Mn}(p,\gamma)^{53}{\rm Fe}$, $^{57}{\rm Co}(p,\gamma)^{58}{\rm Ni}$, and $^{39}{\rm K}(p,\alpha)^{36}{\rm Ar}$ are influential for a large number of model conditions. Furthermore, we found the list of influential reactions identified by previous post-processing studies of CCSN shock-driven nucleosynthesis is likely incomplete, motivating future larger-scale sensitivity studies.

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S. Subedi, Z. Meisel and G. Merz
Mon, 1 Jun 20
40/50

Comments: 15 pages, 7 figures, 3 tables; Accepted to the Astrophysical Journal

Bayesian Inference of the Symmetry Energy of Super-Dense Neutron-Rich Matter from Future Radius Measurements of Massive Neutron Stars [HEAP]

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http://arxiv.org/abs/2005.07216


Using an explicitly isospin-dependent parametric Equation of State (EOS) for the core of neutron stars (NSs) within the Bayesian statistical approach, we infer the EOS parameters of super-dense neutron-rich nuclear matter from three sets of imagined mass-radius correlation data representing typical predictions by various nuclear many-body theories, i.e, the radius stays the same, decreases or increases with increasing NS mass within $\pm 15\%$ between 1.4 M${\odot}$ and 2.0 M${\odot}$. The corresponding average density increases quickly, slowly or slightly decreases as the NS mass increases from 1.4 M${\odot}$ to 2.0 M${\odot}$. Using the posterior probability distribution functions (PDFs) of EOS parameters inferred from GW170817 and NICER radius data for canonical NSs as references, we investigate how future radius measurements of massive NS will improve our knowledge about the EOS of super-dense neutron-rich nuclear matter, especially its symmetry energy term, compared to what people have already learned from analyzing the GW170817 and NICER data. While the EOS of symmetric nuclear matter (SNM) inferred from the three data sets are approximately the same, the corresponding high-density symmetry energies at densities above about $2\rho_0$ are very different, indicating that the radii of massive NSs carry reliable information about the high-density behavior of nuclear symmetry energy with little influence from the remaining uncertainties of the SNM EOS.

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W. Xie and B. Li
Mon, 18 May 20
7/43

Comments: 18 pages with 9 figures

Growth and development of pure Li2MoO4 crystals for rare event experiment at CUP [CL]

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http://arxiv.org/abs/2005.06797


The Center for Underground Physics (CUP) of the Institute for Basic Science (IBS) is searching for the neutrinoless double-beta decay (0{\nu}\b{eta}\b{eta}) of 100Mo in the molybdate crystals of the AMoRE experiment. The experiment requires pure scintillation crystals to minimize internal backgrounds that can affect the 0{\nu}\b{eta}\b{eta} signal. For the last few years, we have been growing and studying Li2MoO4 crystals in a clean-environment facility to minimize external contamination during the crystal growth. Before growing Li2100MoO4 crystal, we have studied Li2natMoO4 crystal growth by a conventional Czochralski (CZ) grower. We grew a few different kinds of Li2natMO4 crystals using different raw materials in a campaign to minimize impurities. We prepared the fused Al2O3 refractories for the growth of ingots. Purities of the grown crystals were measured with high purity germanium detectors and by inductively coupled plasma mass spectrometry. The results show that the Li2MoO4 crystal has purity levels suitable for rare-event experiments. In this study, we present the growth of Li2MoO4 crystals at CUP and their purities.

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J. Son, J. Choe, O. Gileva, et. al.
Fri, 15 May 20
48/65

Comments: 10 pages, 3 figures, INSTR’20 conference (Novosibirsk, Feb. 24-28, 2020)

AMoRE: A search for neutrinoless double-beta decay of 100Mo using low-temperature molybdenum-containing crystal detectors [CL]

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http://arxiv.org/abs/2005.05567


The AMoRE is an experiment to search for neutrinoless double-beta decay of 100Mo in molybdate crystal scintillators using a cryogenic detection technique. The crystals are equipped with metallic magnetic calorimeter sensors that detect both phonon and photon signals at temperatures of a few tens of mK. Simultaneous measurements of thermal and scintillation signals produced by particle interactions in the crystals by MMC sensors provide high energy resolution and efficient particle discrimination. AMoRE-Pilot, an R&D phase with six 48deplCa100MoO4 crystals and a total mass of ~1.9 kg in the final configuration, operated at the 700 m deep Yangyang underground laboratory (Y2L). After completion of the AMoRE-Pilot run at the end of 2018, AMoRE-I with a ~6 kg crystal array comprised of thirteen 48deplCa100MoO4 and five Li2100MoO4 crystals is currently being assembled and installed at Y2L. We have secured 110 kg of 100Mo-isotope-enriched MoO3 powder for the production of crystals for the AMoRE-II phase, which will have ~200 kg of molybdate crystals and operate at Yemilab, a new underground laboratory located ~1,100 m deep in the Handeok iron mine that is currently being excavated and with a scheduled completion date of December 2020. AMoRE-II is expected to improve the upper limit on the effective Majorana neutrino mass to cover the entire inverted hierarchy neutrino mass region: 20-50 meV, in the case when no such decays are observed. Results from AMoRE-Pilot and progress of the preparations for AMoRE-I and AMoRE-II are presented.

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M. Lee
Wed, 13 May 20
32/60

Comments: 10 pages, 4 figures, INSTR’20 conference (Novosibirsk, Feb. 24-28, 2020)

Setup commissioning for an improved measurement of the D(p,gamma)3He cross section at Big Bang Nucleosynthesis energies [CL]

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http://arxiv.org/abs/2005.00002


Among the reactions involved in the production and destruction of deuterium during Big Bang Nucleosynthesis, the deuterium-burning D(p,gamma)3He reaction has the largest uncertainty and limits the precision of theoretical estimates of primordial deuterium abundance. Here we report the results of a careful commissioning of the experimental setup used to measure the cross-section of the D(p,gamma)3He reaction at the Laboratory for Underground Nuclear Astrophysics of the Gran Sasso Laboratory (Italy). The commissioning was aimed at minimising all sources of systematic uncertainty in the measured cross sections. The overall systematic error achieved (< 3 %) will enable improved predictions of BBN deuterium abundance.

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V. Mossa, K. Stöckel, F. Cavanna, et. al.
Mon, 4 May 20
4/55

Comments: 11 pages, 11 figures

Removal of $^{210}$Pb by Etch of Crystalline Detector Sidewalls [CL]

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http://arxiv.org/abs/2005.00488


A potential source of dominant backgrounds for many rare-event searches or screening detectors is from radon daughters, specifically $^{210}$Pb, deposited on detector surfaces, often during detector fabrication. Performing a late-stage etch is challenging because it may damage the detector. This paper describes a late-stage etching technique that reduces surface $^{210}$Pb and $^{210}$Po by $>99\times$ at 90% C.L.

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J. Street, R. Mahapatra, E. Morrison, et. al.
Mon, 4 May 20
27/55

Comments: 6 pages, 6 figures

A facility for mass production of ultra-pure NaI powder for the COSINE-200 experiment [CL]

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http://arxiv.org/abs/2004.13280


COSINE-200 is the next phase of the ongoing COSINE-100 experiment. The main purpose of the experiment is the performance of an unambiguous verification of the annual modulation signals observed by the DAMA experiment. The success of the experiment critically depends on the production of a 200 kg array of ultra-pure NaI(Tl) crystal detectors that have lower backgrounds than the DAMA crystals. The purification of raw powder is the initial but important step toward the production of ultra-pure NaI(Tl) detectors. We have already demonstrated that fractional recrystallization from water solutions is an effective method for the removal of the problematic K and Pb elements. For the mass production of purified powder, a clean facility for the fractional recrystallization had been constructed at the Institute for Basic Science (IBS), Korea. Here, we report the design of the purification process, material recovery, and performance of the NaI powder purification facility.

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K. Shin, J. Choe, O. Gileva, et. al.
Wed, 29 Apr 20
33/75

Comments: Proceeding for INSTR20

Parametric unfolding. Method and restrictions [CL]

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http://arxiv.org/abs/2004.12766


Parametric unfolding of a true distribution distorted due to finite resolution and limited efficiency for the registration of individual events is discussed. Details of the computational algorithm of the unfolding procedure are presented.

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N. Gagunashvili
Tue, 28 Apr 20
68/81

Comments: 14 pages, 9 figures