Tag Archives: High Energy Physics – Phenomenology

Searching for Primordial Black Holes with the Einstein Telescope: impact of design and systematics [CL]

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http://arxiv.org/abs/2304.03160


Primordial Black Holes (PBHs) have recently attracted much attention as they may explain some of the LIGO/Virgo/KAGRA observations and significantly contribute to the dark matter in our universe. The next generation of Gravitational Wave (GW) detectors will have the unique opportunity to set stringent bounds on this putative population of objects. Focusing on the Einstein Telescope (ET), in this paper we analyse in detail the impact of systematics and different detector designs on our future capability of observing key quantities that would allow us to discover and/or constrain a population of PBH mergers. We also perform a population analysis, with a mass and redshift distribution compatible with the current observational bounds. Our results indicate that ET alone can reach an exquisite level of accuracy on the key observables considered, as well as detect up to tens of thousands of PBH binaries per year, but for some key signatures (in particular high–redshift sources) the cryogenic instrument optimised for low frequencies turns out to be crucial, both for the number of observations and the error on the parameters reconstruction. As far as the detector geometry is concerned, we find that a network consisting of two separated L–shaped interferometers of 15 (20)~km arm length, oriented at $45^{\circ}$ with respect to each other performs better than a single triangular shaped instrument of 10 (15)~km arm length, for all the metrics considered.

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G. Franciolini, F. Iacovelli, M. Mancarella, et. al.
Fri, 7 Apr 23
2/50

Comments: 24 pages, 13 figures

Anisotropic Hubble Expansion in Pantheon+ Supernovae [CEA]

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http://arxiv.org/abs/2304.02718


We decompose the Pantheon+ Type Ia supernovae (SN) sample in hemispheres on the sky finding angular variations up to $4$ km/s/Mpc in the Hubble constant $H_0$ both in the SH0ES redshift range $0.0233 < z < 0.15$ and in the extended redshift range $0.01 < z < 0.7$. We assume the $\Lambda$CDM model, so our findings become model dependent in extended redshift ranges. $H_0$ is larger in a hemisphere encompassing the CMB dipole direction. The variations we see exceed the errors on the recent SH0ES determination, $H_0 = 73.04 \pm 1.04$ km/s/Mpc, but are not large enough to explain early versus late Universe discrepancies in the Hubble constant. The removal of low redshift SN leads to a weakening of angular $H_0$ variations, but we confirm that they persist beyond the influence of the Shapley supercluster $z > 0.06$

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R. McConville and E. Colgáin
Fri, 7 Apr 23
6/50

Comments: 4 pages, 7 figures. Comments welcome

Azimuthal fluctuations and number of muons at the ground in muon-depleted proton air showers at PeV energies [CL]

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http://arxiv.org/abs/2304.02988


Muon counting is an effective strategy for discriminating between gamma and hadron-initiated air showers. However, their detection, which requires shielded detectors, is highly costly and almost impossible to implement in large ${\rm km^2}$ environmentally sensitive areas. This work shows that the gamma/hadron discriminators, based on the new $LCm$ variable and the number of muons, have equivalent proton rejection levels at the PeV energies. It is, therefore, possible to build, at an affordable cost, a large, high-performant, wide field-of-view gamma-ray observatory.

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A. Bakalová, R. Conceição, L. Gibilisco, et. al.
Fri, 7 Apr 23
10/50

Comments: N/A

Non-thermal Dark Matter via Lepton Portal: Hubble Tension and Stellar Cooling [CL]

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http://arxiv.org/abs/2304.02904


We propose a new non-thermal dark matter which feebly couples to the standard model charged leptons.The feeble interactions allow it $(1)$ to freeze-in from standard model thermal bath with its relic density being a partial or a whole of the observed dark matter density and $(2)$ to radiatively decay to two photons in the dark matter mass ranges of order keV scale with lifetime larger than the age of Universe.These features make this non-thermal dark matter a realistic realization of dark matter with late-time decay as a solution to Hubble tension.We show that the $68\%$ CL best fit value of $H_{0}=68.3~(69.6)$ km s$^{-1}$Mpc$^{-1}$ compared to CMB+BAO (+LSS) data sets.We then use complimentary stellar cooling data to place stringent constraints on the parameter space.While the universal coupling scenario is excluded, the hierarchical coupling scenario can be tested by future observations on white dwarfs after a careful look into photon annihilation, Primakoff and Bremsstrahlung emission of the dark matter in various stellar systems.The viable parameter space may be linked to anomalies in future X-ray telescopes.

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Z. Xu, R. Zhang and S. Zheng
Fri, 7 Apr 23
13/50

Comments: 19 pages, 7 figures

Right-Handed Neutrino Dark Matter with Forbidden Annihilation [CL]

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http://arxiv.org/abs/2304.02997


The seesaw mechanism with three right-handed neutrinos has one as a well-motivated dark matter candidate if stable and the other two can explain baryon asymmetry via the thermal leptogenesis scenario. We explore the possibility of introducing additional particles to make the right-handed neutrino dark matter in thermal equilibrium and freeze out through a forbidden annihilation channel. Nowadays in the Universe, this forbidden channel can be reactivated by a strong gravitational potential such as the supermassive black hole in our galaxy center. The Fermi-LAT gamma ray data and dark matter relic density require this right-handed neutrino dark matter to have mass below $100\,$GeV and the existence of an additional boson $\phi$ that can be tested at future lepton colliders.

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Y. Cheng, S. Ge, J. Sheng, et. al.
Fri, 7 Apr 23
17/50

Comments: 7 pages, 1 figures

Minihalos as probes of the inflationary spectrum: accurate boost factor calculation and new CMB constraints [CEA]

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http://arxiv.org/abs/2304.02996


Although the spectrum of primordial fluctuations has been accurately measured on scales above $\sim 0.1~\rm{Mpc}$, only upper limits exist on smaller scales. In this study, we investigate generic monochromatic enhancements to the $\Lambda$CDM spectrum that trigger the collapse of ultracompact minihalos (UCMHs) well before standard structure formation. We refine previous treatments by considering a mixed population of halos with different density profiles, that should realistically arise as a consequence of late-time accretion and mergers. Assuming that dark matter (DM) can self-annihilate, we find, as expected, that UCMHs can greatly enhance the annihilation rate around recombination, significantly imprinting the cosmic microwave background (CMB) anisotropies. However, we provide additional insight on the theoretical uncertainties that currently impact that boost and which may affect late-time probes such as the 21 cm line or $\gamma$-ray signals. We derive constraints on the primordial power spectrum on small scales using the ExoCLASS/HYREC codes and the Planck legacy data. We account for the velocity dependence of the DM annihilation cross-section ($s$- or $p$-wave), annihilation channel, the DM particle mass and the inclusion of late-time halo mergers. Our $s$-wave constraints are competitive with previous literature, excluding primordial amplitudes $A_{\star} \gtrsim 10^{-6.5}$ at wavenumbers $k \sim 10^4-10^7 \ \rm{Mpc}^{-1}$. For the first time, we highlight that even $p$-wave processes have constraining power on the primordial spectrum for cross-sections still allowed by currently the strongest astrophysical constraints. Finally, we provide an up-to-date compilation of the most stringent limits on the primordial power spectrum across a wide range of scales.

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G. Abellán and G. Facchinetti
Fri, 7 Apr 23
44/50

Comments: 43 pages, 12 figures. Comments welcome!

Eternal binaries [CL]

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http://arxiv.org/abs/2304.02039


The two-body problem is extensively studied in open systems and asymptotically flat spacetimes. However, there are many systems where radiation is trapped: they range from radiating charges in cavities to low-energy excitations of massive degrees of freedom, to anti-de Sitter spacetimes. Here, we study the problem of motion of a pointlike particle orbiting a massive compact object inside a cavity. We first show that – assuming circular motion – there are initial conditions for which the self-force vanishes and the binary is eternal. We then consider the evolution of the system under radiation reaction in a toy model which we argue captures the essentials of orbiting particles. We show that eternal circular binaries may exist. We also show that the presence of cavity modes leads to chaos in regimes of strong coupling or when the system is initialized close enough to a resonance. Our results have implications for physics in anti-de Sitter spacetimes and possibly for binaries evolving within dark matter haloes, if it consists on massive fundamental fields.

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J. Redondo-Yuste, V. Cardoso, C. Macedo, et. al.
Thu, 6 Apr 23
2/76

Comments: 21 pages, 17 figures

A novel integrated Sachs-Wolfe effect from Early Dark Energy [CEA]

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http://arxiv.org/abs/2304.02028


We study the nonlinear effects of minimally coupled, massless, cosmological scalar fields on the cosmic microwave background (CMB). These fields can exhibit post-recombination parametric resonance and subsequent nonlinear evolution leading to novel contributions to the gravitational potential. We compute the resulting contributions to the CMB temperature anisotropies through the time-variation of the gravitational potential (i.e., the integrated Sachs-Wolfe (ISW) effect). We find that fields that constitute 5% of the total energy density and become dynamical at $z_c \simeq 10^{4}$ can produce marginally observable ISW signals at multipoles $\ell \simeq 2000$. Fields that become dynamical at earlier times and/or have initial displacements at a flatter part of their potential, produce ISW contributions that are significantly larger and at higher multipoles. We calculate these dynamics and the resulting evolution of gravitational perturbations using analytic estimates alongside detailed nonlinear lattice simulations, which couple scalar fields and cosmological fluids to a perturbed metric. Finally, we discuss the possibility of detecting these features with future high-resolution CMB observations.

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T. Smith, J. Jr., M. Amin, et. al.
Thu, 6 Apr 23
9/76

Comments: 12 pages, 6 figures, comments welcome

Gravitational waves from cosmic strings associated with pseudo-Nambu-Goldstone dark matter [CL]

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http://arxiv.org/abs/2304.02506


We study stochastic gravitational waves from cosmic strings generated in an ultraviolet-complete model for pseudo-Nambu-Goldstone dark matter with a hidden $\mathrm{U(1)}$ gauge symmetry. The dark matter candidate in this model can naturally evade direct detection bounds and easily satisfy other phenomenological constraints. The bound on the dark matter lifetime implies an ultraviolet scale higher than $10^9~\mathrm{GeV}$. The spontaneous $\mathrm{U(1)}$ symmetry breaking at such a high scale would induce cosmic strings with high tension, resulting in a stochastic gravitational wave background with a high energy density. We investigate the constraints from current gravitational wave experiments as well as the future sensitivity. We find that most of the viable parameter points could be well studied in future gravitational wave experiments.

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Z. Qiu and Z. Yu
Thu, 6 Apr 23
16/76

Comments: 23 pages, 6 figures

Quantitative constraints on modified gravity paradigms [CEA]

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http://arxiv.org/abs/2304.02522


We use low-redshift background cosmology data to place quantitative constraints on three separate modified gravity models, each of which aims to explain the low-redshift acceleration through a different physical mechanism. The Lifshitz cosmology is effectively a parametric extension of the canonical $\Lambda$CDM model, where a time-dependent cosmological constant originates from vacuum energy. The Infinite Statistics model is also a parametric extension of $\Lambda$CDM, where the dark energy is dynamic and originates from the curvature of a dual space-time. We show that the data restricts the additional parameters in these models to be consistent with their $\Lambda$CDM values, and in particular that it implies that the theoretically predicted value for a dimensionless coupling parameter in the Lifshitz model is ruled out at more than six standard deviations. In the Regge-Teitelboim model, gravity is described by embedding the usual space-time manifold in a fixed higher-dimensional background, and there is no parametric $\Lambda$CDM limit. We study several separate realizations of the model, respectively introduced by Davidson, by Fabi \textit{et al.}, and by Stern \& Xu, and show that the first two are ruled out by the low-redshift data we use, while the latter is consistent with this data but requires a non-standard value of the matter density. Overall, our analysis highlights the tight constraints imposed by current data on the allowed low-redshift deviations from the standard $\Lambda$CDM background evolution.

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S. Pinto, A. Cabral and C. Martins
Thu, 6 Apr 23
39/76

Comments: 11 pages, 8 figures, Phys. Rev. D (in press)

Testing generalized neutrino interactions with PTOLEMY [CL]

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http://arxiv.org/abs/2304.02505


There are several unanswered questions regarding neutrinos which pave the way for physics beyond the standard model (SM) of particle physics. Generalized interactions of neutrinos provide a way to characterize these effects in a manner which is even more general than the oft-studied non-standard neutrino interactions. These interactions are described by higher dimensional operators maintaining the SM gauge symmetries. On the other hand cosmic neutrino background, although yet to be detected directly, is a robust prediction of the SM and the standard cosmology. We perform a global analysis of the relevant generalized neutrino interactions which are expressly relevant for the proposed cosmic neutrino detector PTOLEMY. The electron spectrum due to the capture of cosmic neutrinos on radioactive tritium gets modified due to the presence of these generalized interactions. We also show how the differential electron spectrum is sensitive to the finite experimental resolution, mass of the lightest neutrino eigenstate, the strength of these interactions and the ordering of neutrino mass.

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I. Banerjee, U. Dey, N. Nath, et. al.
Thu, 6 Apr 23
44/76

Comments: 22 pages, 5 figures, 5 tables

Primordial Black Hole Leptogenesis in Supersymmetry [CL]

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http://arxiv.org/abs/2304.02604


We have studied the role of Hawking evaporation of primordial black hole in the production of the supersymmetric particles like sneutrinos – the super-partner of heavy right handed neutrinos. Considering lepton number violating decays of such particles and $CP$ violating phases due to soft supersymmetry breaking terms, we have obtained the baryonic asymmetry of the universe which depends on the mass of primordial black holes. Apart from CMB and BBN constraints on such mass, we have shown more stringent upper bound on this mass from the requirement of black hole evaporation temperature to be above the temperature required for almost first order phase transition so that leptogenesis could create the observed baryonic asymmetry. We have shown how the primordial black hole mass, heavy right handed neutrino mass and soft supersymmetry breaking parameters are related from the requirement of successful leptogenesis and the allowed parameter space to avoid gravitino problem. Considering experimental constraint on branching ratio of $\mu \rightarrow e \gamma $, we have shown the connection of right handed neutrino mass scale with the lower bound of the typical mass scale of supersymmetric particles.

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S. Khan and R. Adhikari
Thu, 6 Apr 23
46/76

Comments: 14 pages, 3 figures

Temperature and Strong Magnetic Field Effects in Dense Matter [CL]

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http://arxiv.org/abs/2304.02454


We study consistently the effects of magnetic field on hot and dense matter. In particular, we look for differences that arise due to assumptions that reproduce the conditions produced in particle collisions or astrophysical scenarios, such as in the core of fully evolved neutron stars. We assume the magnetic field to be either constant or follow a profile extracted from general relativity calculations of magnetars and make use of two realistic models that can consistently describe chiral symmetry restoration and deconfinement to quark matter, {the CMF and the PNJL models}. We find that net isospin, strangeness, and {weak} chemical equilibrium with leptons can considerably change the effects of temperature and magnetic fields on particle content and deconfinement in dense matter. We finish by discussing the possibility of experimentally detecting quark deconfinement in dense and/or hot matter and the possible role played by magnetic fields.

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J. Peterson, P. Costa, R. Kumar, et. al.
Thu, 6 Apr 23
47/76

Comments: N/A

Imprints of a Supercooled Universe in the Gravitational Wave Spectrum from a Cosmic String network [CEA]

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http://arxiv.org/abs/2304.02636


A network of cosmic strings (CS), if present, would continue emitting gravitational waves (GW) as it evolves throughout the history of the Universe. This results in a characteristic broad spectrum making it a perfect source to infer the expansion history. In particular, a short inflationary period caused by a supercooled phase transition would cause a drop in the spectrum at frequencies corresponding to that event. However, the impact on the spectrum is similar to the ones caused by an early matter-dominated era or from particle production, making it difficult to disentangle these different physical origins. We point out that, in the case of a short inflationary period, the GW spectrum receives an additional contribution from the phase transition itself. This leads to a characteristic imprint of a peak on top of a wide plateau both visible at future GW observatories.

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F. Ferrer, A. Ghoshal and M. Lewicki
Thu, 6 Apr 23
54/76

Comments: 12 pages without references, 2 Figures, comments are welcome

Gravitational Waves Produced by Domain Walls During Inflation [CL]

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http://arxiv.org/abs/2304.02361


We study the properties of the stochastic gravitational wave background (SGWB) produced by domain walls (DWs) during inflation without forming a network. We numerically simulate the DW production caused by a second-order phase transition and calculate the SGWB spectrum using a $1000\times1000\times1000$ lattice. We show that the SGWB can be observed directly by future terrestrial and spatial gravitational wave detectors and through the B-mode spectrum in CMB. This signal can also explain the common noise process observed by pulsar timing array experiments. With numerical simulations, we derive an empirical formula for the strength and qualitative features of the SGWB spectrum. The details of the SGWB spectrum also contain information about the later evolution of the universe.

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H. An and C. Yang
Thu, 6 Apr 23
68/76

Comments: 5 pages, 7 figures + appendix

Gravitational echoes of lepton number symmetry breaking with light and ultralight Majorons [CL]

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http://arxiv.org/abs/2304.02399


We formulate a version of the low-scale Majoron model equipped with an inverse seesaw mechanism featuring lepton-number preserving dimension-6 operators in the scalar potential. Contrary to its dimension-4 counterpart, we find that the model can simultaneously provide light and ultralight Majorons, neutrino masses and their mixing, while featuring strong first-order cosmological phase transitions associated to the spontaneous breaking of the lepton number and the electroweak symmetries in the early Universe. We show by a detailed numerical analysis that under certain conditions on the parameter space accounted for in collider physics, the model can be probed via the primordial gravitational wave spectrum potentially observable at LISA and other planned facilities.

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A. Addazi, A. Marcianò, A. Morais, et. al.
Thu, 6 Apr 23
72/76

Comments: 29 pages, 7 figures

Axion-photon conversion of GRB221009A [HEAP]

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http://arxiv.org/abs/2304.01819


The newly observed gamma ray burst GRB221009A exhibits the existence of 10~TeV-scale photons, and the axion-photon conversion has been suggested as a candidate to explain such energetic features of GRB221009A. In this work we adopt a model to calculate the conversion probability of the energetic photons from GRB221009A to the Earth. The result shows that the penetration probability of photons with energy above $10^1$~TeV can be up to $10^{-2}-10^{-4}$ depending on the coupling constant $g_{a\gamma}$ and the axion mass $m_a$, together with the magnetic field parameters of the host galaxy of GRB221009A. By comparing the results in this article with the data from LHAASO, we can obtain more precise constraints on the ranges of these parameters.

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L. Wang and B. Ma
Wed, 5 Apr 23
3/62

Comments: 7 latex pages, 5 figures

Hybrid stars with reactive interfaces: analysis within the Nambu-Jona-Lasinio model [CL]

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http://arxiv.org/abs/2304.01898


It has been shown recently that quark-hadron conversions at the interface of a hybrid star may have a key role on the dynamic stability of the compact object. In this work we perform a systematic study of hybrid stars with reactive interfaces using a model-agnostic piecewise-polytropic hadronic equation of state and the Nambu-Jona-Lasinio model for three-flavor quark matter. For the hadronic phase we use a soft, an intermediate and a stiff parametrization that match at $1.1 n_0$ {with predictions} based on chiral effective field theory (cEFT) interactions. In the NJL Lagrangian we include scalar, vector and ‘t Hooft interactions. The vector coupling constant $g_{v}$ is treated as a free parameter. We also consider that there is a split between the deconfinement and the chiral phase transitions which is controlled by changing the conventional value of the vacuum pressure $-\Omega_{0}$ in the NJL thermodynamic potential by $-\left(\Omega_{0}+\delta \Omega_{0}\right)$, being $\delta \Omega_{0}$ a free parameter. We analyze the mass-radius ($M$-$R$) relation in the case of rapid ($\tau \ll 1 \, \mathrm{ms}$) and slow ($\tau \gg 1 \, \mathrm{ms}$) conversions, being $\tau$ the reaction timescale. In the case of slow interface reactions we find $M$-$R$ curves with a cusp at the maximum mass point where a pure hadronic branch and a slow-stable hybrid star (SSHS) branch coincide. We find that the length of the slow-stable branch grows with the increase of the transition density and the energy density jump at the hadron-quark interface. We calculate the tidal deformabilities of SSHSs and analyse them in the light of the GW170817 event.

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C. Lenzi, G. Lugones and C. Vasquez
Wed, 5 Apr 23
7/62

Comments: 12 pages, 4 figures, to be published in Physical Review D

Kinetic relaxation and Bose-star formation in multicomponent dark matter- I [CEA]

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http://arxiv.org/abs/2304.01985


Using wave kinetics, we estimate the emergence time-scale of gravitating Bose-Einstein condensates/Bose stars in the kinetic regime for a general multicomponent Schr\”{o}dinger-Poisson (SP) system. We identify some effects of the diffusion and friction pieces in the wave-kinetic Boltzmann equation (at leading order in perturbation theory) and provide estimates for the kinetic nucleation rate of condensates. We test our analysis using full $3+1$ dimensional simulations of multicomponent SP system. With an eye towards applications to multicomponent dark matter, we investigate two general cases in detail. First is a massive spin-$s$ field with $N=2s+1$ components (scalar $s=0$, vector $s=1$ and tensor $s=2$). We find that for a democratic population of different components, the condensation time-scale is $\tau_{(s)}\approx \tau_0\times N$, where $\tau_0$ is the condensation time scale for the scalar case. Second is the case of two scalars with different boson masses. In this case, we map-out how the condensation time depends on the ratios of their average mass densities and boson masses, revealing competition and assistance between components, and a guide towards which component condenses first. For instance, with $m_1 < m_2$ and not too disparate mass densities, we verify that the time scale of condensation of the first species quickly becomes independent of $m_2/m_1$, whereas for equal average number densities, the emergence time scale decreases with increasing $m_2/m_1$.

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M. Jain, M. Amin, J. Thomas, et. al.
Wed, 5 Apr 23
13/62

Comments: 8 pages + 3 appendices, 5 figures. Videos from simulations are available at this https URL

Black hole superradiant instability for massive spin-2 fields [CL]

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http://arxiv.org/abs/2304.01265


Due to coherent superradiant amplification, massive bosonic fields can trigger an instability in spinning black holes, tapping their energy and angular momentum and forming macroscopic Bose-Einstein condensates around them. This phenomenon produces gaps in the mass-spin distribution of astrophysical black holes, a continuous gravitational-wave signal emitted by the condensate, and several environmental effects relevant for gravitational-wave astronomy and radio images of black holes. While the spectrum of superradiantly unstable mode is known in great detail for massive scalar (spin-0) and vector (spin-1) perturbations, so far only approximated results were derived for the case of massive tensor (spin-2) fields, due to the nonseparability of the field equations. Here, solving a system of ten elliptic partial differential equations, we close this program and compute the spectrum of the most unstable modes of a massive spin-2 field for generic black-hole spin and boson mass, beyond the hydrogenic approximation and including the unique dipole mode that dominates the instability in the spin-2 case. We find that the instability timescale for this mode is orders of magnitude shorter than for any other superradiant mode, yielding much stronger constraints on massive spin-2 fields. These results pave the way for phenomenological studies aimed at constraining beyond Standard Model scenarios, ultralight dark matter candidates, and extensions to General Relativity using gravitational-wave and electromagnetic observations, and have implications for the phase diagram of vacuum solutions of higher-dimensional gravity.

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O. Dias, G. Lingetti, P. Pani, et. al.
Wed, 5 Apr 23
24/62

Comments: 5+1 pages, 2+1 figures

A novel prediction for secondary positrons and electrons in the Galaxy [HEAP]

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http://arxiv.org/abs/2304.01261


The Galactic flux of cosmic-ray (CR) positrons in the GeV to TeV energy range is very likely due to different Galactic components. One of these is the inelastic scattering of CR nuclei with the atoms of the interstellar medium. The precise amount of this component determines the eventual contribution from other sources. We present here a new estimation of the secondary CR positron flux by incorporating the latest results for the production cross sections of $e^\pm$ from hadronic scatterings calibrated on collider data. All the reactions for CR nuclei up to silicon scattering on both hydrogen and helium are included. The propagation models are derived consistently by fits on primary and secondary CR nuclei data. Models with a small halo size ($\leq 2$ kpc) are disfavored by the nuclei data although the current uncertainties on the beryllium nuclear cross sections may impact this result. The resulting positron flux shows a strong dependence on the Galactic halo. Within the most reliable propagation models, the positron flux matches the data for energies below 1 GeV. We verify that secondary positrons contribute less than $70\%$ of the data already above a few GeV, demonstrating that an excess of positrons is already present at very low energies. At larger energies, our predictions are below the data with the discrepancy becoming more pronounced. Our predictions are provided together with uncertainties due to propagation and hadronic cross sections. In addition to the predictions of positrons, we provide new predictions also for the secondary CR electron flux.

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M. Mauro, F. Donato, M. Korsmeier, et. al.
Wed, 5 Apr 23
33/62

Comments: 14 pages, 8 figures. Appendix adds 7 pages, 4 figures and 2 tables

On the primordial black hole formation in hybrid inflation [CEA]

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http://arxiv.org/abs/2304.01249


We revisit the scenario of primordial black hole (PBH) formation from large curvature perturbations generated during the waterfall phase transition in hybrid inflation models. In a minimal setup considered in the literature, the mass and abundance of PBHs are correlated and astrophysical size PBHs tend to be overproduced. This is because a longer length scale for curvature perturbations (or a larger PBH mass) requires a longer waterfall regime with a flatter potential, which results in overproduction of curvature perturbations. However, in this paper, we discuss that the higher-dimensional terms for the inflaton potential affect the dynamics during the waterfall phase transition and show that astrophysical size PHBs of order $10^{17\text{–}23} \, {\rm g}$ (which can explain the whole dark matter) can form in some parameter space consistently with any existing constraints. The scenario can be tested by observing the induced gravitational waves from scalar perturbations by future gravitational wave experiments, such as LISA.

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Y. Tada and M. Yamada
Wed, 5 Apr 23
40/62

Comments: 13 pages, 8 figures

The dipolar death of massive gravity [CL]

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http://arxiv.org/abs/2304.01252


We study extreme-mass-ratio systems in theories admitting the Schwarzschild solution and propagating a massive graviton. We show that, in addition to small corrections to the quadrupolar and higher-order modes, a dipolar mode is excited in these theories and we quantify its excitation. While LIGO-Virgo-KAGRA observations are not expected to impose meaningful constraints in the dipolar sector, future observations by the Einstein Telescope or by LISA, together with bounds from dispersion relations, can rule out theories of massive gravity admitting vacuum General Relativistic backgrounds. For the bound to be circumvented, one needs to move away from Ricci-flat solutions, and enter a territory where constraints based on wave propagation and dispersion relations are not reliable.

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V. Cardoso, F. Duque, A. Maselli, et. al.
Wed, 5 Apr 23
48/62

Comments: 4 pages plus Supplemental Material

Freeze-in of WIMP dark matter [CL]

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http://arxiv.org/abs/2304.00908


We propose a novel scenario for dark matter (DM) in which weakly interacting massive particles (WIMPs) can freeze-in due to a first-order phase transition (FOPT) in the early Universe. The FOPT dilutes the preexisting DM density to zero, and leads to a sudden change in DM mass that prevents WIMPs from re-equilibrating due to their large mass-to-temperature ratio. Following the FOPT, WIMPs are produced via a freeze-in process, even though their interactions are NOT feeble. We demonstrate this concept using a simplified model and then realize the scenario in a realistic model with a delayed electroweak phase transition. Our work extends the category of WIMP DM and opens up a new direction for the freeze-in mechanism.

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X. Wong and K. Xie
Tue, 4 Apr 23
11/111

Comments: 4 pages + 3 figures + references

Searching for dark matter subhalos in the Fermi-LAT catalog with Bayesian neural networks [HEAP]

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http://arxiv.org/abs/2304.00032


About a third of the $\gamma$-ray sources detected by the Fermi Large Area Telescope (Fermi-LAT) remain unidentified, and some of these could be exotic objects such as dark matter subhalos. We present a search for these sources using Bayesian neural network classification methods applied to the latest 4FGL-DR3 Fermi-LAT catalog. We first simulate the gamma-ray properties of dark matter subhalos using models from N-body simulations and semi-analytical approaches to the subhalo distribution. We then assess the detectability of this sample in the 4FGL-DR3 catalog using the Fermi-LAT analysis tools. We train our Bayesian neural network to identify candidate dark matter subhalos among the unidentified sources in the 4FGL-DR3 catalog. Our results allow us to derive conservative bounds on the dark matter annihilation cross section by excluding unidentified sources classified as astrophysical-like by our networks. We estimate the number of candidate dark matter subhalos for different dark matter masses and provide a publicly available list for further investigation. Our bounds on the dark matter annihilation cross section are comparable to previous results and become particularly competitive at high dark matter masses.

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A. Butter, M. Krämer, S. Manconi, et. al.
Tue, 4 Apr 23
27/111

Comments: 31 pages, 14 figures

Can supermassive black holes triggered by general QCD axion bubbles? [CL]

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http://arxiv.org/abs/2304.00939


The supermassive black holes (SMBHs) are ubiquitous in the center of galaxies, although the origin of their massive seeds is still unknown. In this paper, we investigate the SMBHs formation from the general QCD axion bubbles. In this case, the primordial black holes (PBHs) are considered as the seeds of SMBHs, which are generated from the QCD axion bubbles due to an additional Peccei-Quinn (PQ) symmetry breaking after inflation. The QCD axion bubbles are formed when the QCD axion starts to oscillate during the QCD phase transition (PT). We consider the general case in which the QCD axion bubbles are formed with the bubble effective angle $\theta_{\rm eff}\in(0, \, \pi]$, leading to the minimum PBH mass $\sim\mathcal{O}(10^4-10^7)M_\odot$ with $\theta_{\rm eff}\sim\pi$ to $\pi/3$ for the axion scale $f_a\sim\mathcal{O}(10^{16})\, \rm GeV$. The PBHs at this mass region may be the seeds of SMBHs.

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H. Li, Y. Peng, W. Chao, et. al.
Tue, 4 Apr 23
39/111

Comments: 7 pages, 4 figures

Solar radio emissions and ultralight dark matter [CL]

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http://arxiv.org/abs/2304.01056


Ultralight axions and dark photons are well-motivated dark matter candidates. Inside the plasma, once the mass of ultralight dark matter candidates equals the plasma frequency, they can resonantly convert into electromagnetic waves, due to the coupling between the ultralight dark matter particles and the standard model photons. The converted electromagnetic waves are monochromatic. In this article, we review the development of using radio detectors to search for ultralight dark matter conversions in the solar corona and solar wind plasma.

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H. An, S. Ge and J. Liu
Tue, 4 Apr 23
51/111

Comments: 13 pages, 3 figures. An invited review for the special issue “Solar Radio Emissions” in the journal Universe

Reanalysis of the Systematic Uncertainties in Cosmic-Ray Antiproton Flux [HEAP]

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http://arxiv.org/abs/2304.00760


Recent studies on cosmic rays (CRs) have reported the possibility of an excess in the antiproton flux around $10-20$ GeV. However, the associated systematic uncertainties have impeded the interpretation of these findings. In this study, we conduct a global Bayesian analysis to constrain the propagation parameters and evaluate the CR antiproton spectrum, while comprehensively accounting for uncertainties associated with interstellar CR propagation, production cross sections for antiprotons and other secondaries, and the charge and energy dependent effects of solar modulation. We establish that the most recent AMS-02 $\bar{p}$ spectrum is in agreement with a pure secondary origin. Based on this, we establish upper limits on dark matter (DM) annihilation. We also determine that the AMS-02 data favors the empirical hadronic interaction models over phenomenological ones. Finally, we find that the latest AMS-02 antiproton data from 2011 to 2018 disfavors the antiproton excess at $\mathcal{O}$(10) GeV and the corresponding DM interpretation that can simultaneously account for the Galactic Center excess in the gamma-ray observation.

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X. Lv, X. Bi, K. Fang, et. al.
Tue, 4 Apr 23
74/111

Comments: 11 pages, 7 figures

Investigating the gamma-ray burst from decaying MeV-scale axion-like particles produced in supernova explosions [HEAP]

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http://arxiv.org/abs/2304.01060


We investigate the characteristics of the gamma-ray signal following the decay of MeV-scale Axion-Like Particles (ALPs) coupled to photons which are produced in a Supernova (SN) explosion. This analysis is the first to include the production of heavier ALPs through the photon coalescence process, enlarging the mass range of ALPs that could be observed in this way and giving a stronger bound from the observation of SN 1987A. Furthermore, we present a new analytical method for calculating the predicted gamma-ray signal from ALP decays. With this method we can rigorously prove the validity of an approximation that has been used in some of the previous literature, which we show here to be valid only if all gamma rays arrive under extremely small observation angles (i.e. very close to the line of sight to the SN). However, it also shows where the approximation is not valid, and offers an efficient alternative to calculate the ALP-induced gamma-ray flux in a general setting when the observation angles are not guaranteed to be small. We also estimate the sensitivity of the Fermi Large Area Telescope (Fermi-LAT) to this gamma-ray signal from a future nearby SN and show that in the case of a non-observation the current bounds on the ALP-photon coupling $ g_{a\gamma} $ are strengthened by about an order of magnitude. In the case of an observation, we show that it may be possible to reconstruct the product $ g_{a\gamma}^2 m_a $, with $ m_a $ the mass of the ALP.

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E. Müller, F. Calore, P. Carenza, et. al.
Tue, 4 Apr 23
83/111

Comments: 28 pages, 9 figures

Spontaneous Human Combustion rules out all standard candidates for Dark Matter [CL]

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http://arxiv.org/abs/2304.00319


We argue that the reported cases of Spontaneous Human Combustion (SHC) are most likely due to the impact of the human body with an extremely high energy particle like cosmic rays or Dark Matter. Normal and antimatter cosmic rays and classical weakly-interacting massive particles (WIMPs) with energies of GeV to ZeV can be easily ruled out due to their inability to dump enough energy into a small region of human tissue, leaving as the single remaining candidate massive Dark Matter particles. While primordial Black Holes would appear to be very good candidates for inducing the SHC phenomenon, we show that the estimated local Dark Matter density requires that the particles have masses of $\sim 10$\,kg, clearly ruling out this candidate. All of the other classic DM candidates — from scalar and pseudo-scalar spin 1/2 and spin 2 gauge singlets to nuclearitic strange quark “bowling balls” — can be ruled out. Axions tailored to solve the CP-problem also cannot be invoked, no matter what mass is considered. The only particles left are massive mega-axions (MaMAs), for which there are an infinite number of possible string models.

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F. Hessman and J. Wheeler
Tue, 4 Apr 23
88/111

Comments: N/A

Energy flow in Ultra High Energy Cosmic Ray interactions as a probe of thermalization and potential solution to the Muon puzzle [CL]

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http://arxiv.org/abs/2304.00294


Indicators that illustrate the formation of a strongly interacting thermalized matter of partons have been observed in high-multiplicity proton-proton, proton-nucleus, and nucleus-nucleus collisions at RHIC and LHC energies. Strangeness enhancement in such ultra-relativistic heavy-ion collisions is considered to be a consequence of this thermalized phase, known as quark-gluon plasma (QGP). Simultaneously, proper modeling of hadronic energy fraction in interactions of ultra-high energy cosmic rays (UHECR) has been proposed as a solution for the muon puzzle. These interactions have center-of-mass collision energies in the order of LHC or higher, indicating that the possibility of a thermalized partonic state cannot be overlooked in UHECR-air interactions. This work investigates the hadronic energy fraction and strangeness enhancement to explore QGP-like phenomena in UHECR-air interactions using various high-energy hadronic models. A thermalized system with statistical hadronization is considered through the EPOS LHC model, while PYTHIA 8, QGSJET II-04, and SYBILL 2.3d consider string fragmentation in the absence of any thermalization. We have found that EPOS LHC gives a better description of strangeness enhancement as compared to other models. We conclude that adequately treating all the relevant effects and further retuning the models is necessary to explain the observed effects.

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R. Scaria, S. Deb, C. Singh, et. al.
Tue, 4 Apr 23
109/111

Comments: 7 pages and 6 figures. Submitted for publication

Polarization Formalism for ALP-induced X-ray Emission from Magnetars [HEAP]

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http://arxiv.org/abs/2303.17641


Missions like NASA’s Imaging X-ray Polarimetry Explorer (IXPE) are poised to provide an unprecedented view of the Universe in polarized X-rays. Polarization probes physical anisotropies, a fact exploited by particle physicists to look for the anisotropic $a\boldsymbol{E}\cdot\boldsymbol{B}$ operator in the axion-like-particle (ALP) Lagrangian. Such studies have typically focused on polarization in the radio and microwaves, through local or cosmic birefringence effects. To such polarization studies we add X-rays emanating from magnetars — a class of neutron stars with near-critical strength magnetic fields — that are important targets for IXPE. ALPs produced in the neutron star core convert to X-rays in the magnetosphere; such X-rays are polarized along the direction parallel to the dipolar magnetic field at the point of conversion. We develop the full theoretical formalism for ALP-induced polarization in the presence of dipolar magnetic fields. For uncorrelated photon and ALP production mechanisms, we completely disentangle the ALP contributions to the Stokes parameters in terms of the ALP intensity, the ALP-to-photon conversion probability, and the ALP-induced birefringence. In the proper limit, our results demonstrate that the inclusion of ALPs suppresses the observed degree of circular polarization compared to its pure astrophysical value. Our results can also be used to impose limits on ALP couplings with IXPE polarization data from magnetars 4U 0142+61 and 1RXS J170849.0-400910, the subject of upcoming work.

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J. Fortin and K. Sinha
Mon, 3 Apr 23
3/53

Comments: 1+22 pages, 2 figures

Could compact stars in globular clusters constrain dark matter? [HEAP]

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http://arxiv.org/abs/2303.18009


The dark matter content of globular clusters, highly compact gravity-bound stellar systems, is unknown. It is also generally unknowable, due to their mass-to-light ratios typically ranging between 1$-$3 in solar units, accommodating a dynamical mass of dark matter at best comparable to the stellar mass. That said, recent claims in the literature assume densities of dark matter around 1000 GeV/cm$^3$ to set constraints on its capture and annihilation in white dwarfs residing in the globular cluster M4, and to study a number of other effects of dark matter on compact stars. Motivated by these studies, we use measurements of stellar kinematics and luminosities in M4 to look for a dark matter component via a spherical Jeans analysis; we find no evidence for it, and set the first empirical limits on M4’s dark matter distribution. Our density upper limits, a few $\times \ 10^4$ GeV/cm$^3$ at 1 parsec from the center of M4, do not negate the claims (nor confirm them), but do preclude the use of M4 for setting limits on non-annihilating dark matter kinetically heating white dwarfs, which require at least $10^5$ GeV/cm$^3$ densities. The non-robust nature of globular clusters as dynamical systems, combined with evidence showing that they may originate from molecular gas clouds in the absence of dark matter, make them unsuitable as laboratories to unveil dark matter’s microscopic nature in current or planned observations.

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R. Garani, N. Raj and J. Reynoso-Cordova
Mon, 3 Apr 23
6/53

Comments: 10 pages revtex4 + references, 3 figures, 1 table

Scale-Invariant Model for Gravitational Waves and Dark Matter [CEA]

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http://arxiv.org/abs/2303.18122


We have conducted a revised analysis of the first-order phase transition that is associated with symmetry breaking in a classically scale-invariant model that has been extended with a new $SU(2)$ gauge group. By incorporating recent developments in the understanding of supercooled phase transitions, we were able to calculate all of its features and significantly limit the parameter space. We were also able to predict the gravitational wave spectra generated during this phase transition and found that this model is well-testable with LISA. Additionally, we have made predictions regarding the relic dark matter abundance. Our predictions are consistent with observations but only within a narrow part of the parameter space. We have placed significant constraints on the supercool dark matter scenario by improving the description of percolation and reheating after the phase transition, as well as including the running of couplings. Finally, we have also analyzed the renormalization-scale dependence of our results.

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A. Karam, M. Kierkla and B. Świeżewska
Mon, 3 Apr 23
13/53

Comments: 18+9 pages, 9 figures, invited talk given at CORFU2022, summarizing the results of arXiv:2210.07075

Cosmological Signatures of Mass Varying Dark Matter [CEA]

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http://arxiv.org/abs/2303.17947


Nontrivial dark sector physics continues to be an interesting avenue in our quest to the nature of dark matter. In this paper, we study the cosmological signatures of mass-varying dark matter where its mass changes from zero to a nonzero value in the early Universe. We compute the changes in various observables, such as, the matter and the cosmic microwave background anisotropy power spectrum. We explain the origin of the effects and point out a qualitative similarity between this model and a warm dark matter cosmology with no sudden mass transition. We also do a simple frequentist analysis of the linear matter power spectrum to estimate the constraint on the parameters of this model from latest cosmological observation data.

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A. Das, S. Das and S. Sethi
Mon, 3 Apr 23
23/53

Comments: 7 pages, 6 figures

The cosmological constant is probably still zero [CL]

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http://arxiv.org/abs/2303.17723


We consider a wide class of four-dimensional effective field theories in which gravity is coupled to multiple four-forms and their dual scalar fields, with membrane sources charged under the corresponding three-form potentials. Four-form flux, quantised in units of the membrane charges, generically generates a landscape of vacua with a range of values for the cosmological constant that is scanned through membrane nucleation. We list various ways in which the landscape can be made sufficiently dense to be compatible with observations of the current vacuum without running into the empty universe problem. Further, we establish the general criteria required to ensure the absolute stability of the Minkowski vacuum under membrane nucleation and the longevity of those vacua that are parametrically close by. This selects the current vacuum on probabilistic grounds and can even be applied in the classic model of Bousso and Polchinski, albeit with some mild violation of the membrane weak gravity conjecture. We present other models where the membrane weak gravity conjecture is not violated but where the same probabilistic methods can be used to tackle the cosmological constant problem.

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Y. Liu, A. Padilla and F. Pedro
Mon, 3 Apr 23
24/53

Comments: 29 pages

Probing darK Matter Using free leptONs: PKMUON [CL]

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http://arxiv.org/abs/2303.18117


We propose a new method to detect sub-GeV dark matter, through their scatterings from free leptons and the resulting kinematic shifts. Specially, such an experiment can detect dark matter interacting solely with muons. The experiment proposed here is to directly probe muon-philic dark matter, in a model-independent way. Its complementarity with the muon on target proposal, is similar to, e.g. XENON/PandaX and ATLAS/CMS on dark matter searches. Moreover, our proposal can work better for relatively heavy dark matter such as in the sub-GeV region. We start with a small device of a size around 0.1 to 1 meter, using atmospheric muons to set up a prototype. Within only one year of operation, the sensitivity on cross section of dark matter scattering with muons can already reach $\sigma_D\sim 10^{-19 (-20,\,-18)}\rm{cm}^{2}$ for a dark mater $\rm{M_D}=100\, (10,\,1000)$ MeV. We can then interface the device with a high intensity muon beam of $10^{12}$/bunch. Within one year, the sensitivity can reach $\sigma_D\sim 10^{-27 (-28,\,-26)}\rm{cm}^{2}$ for $\rm{M_D}=100\, (10,\,1000)$ MeV.

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A. Ruzi, C. Zhou, X. Sun, et. al.
Mon, 3 Apr 23
31/53

Comments: 5 pages, 3 figures, muons enlighten darkness

Inflationary gravitational wave background as a tail effect [CL]

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http://arxiv.org/abs/2303.17985


The free propagator of a massless mode in an expanding universe can be written as a sum of two terms, a lightcone and a tail part. The latter describes a subluminal (time-like) signal. We show that the inflationary gravitational wave background, influencing cosmic microwave background polarization, and routinely used for constraining inflationary models through the so-called $r$ ratio, originates exclusively from the tail part.

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N. Jokela, K. Kajantie, M. Laine, et. al.
Mon, 3 Apr 23
34/53

Comments: 8 pages

Hydrodynamical constraints on bubble wall velocity [CEA]

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http://arxiv.org/abs/2303.18216


Terminal velocity reached by bubble walls in first order phase transitions is an important parameter determining both primordial gravitational-wave spectrum and production of baryon asymmetry in models of electroweak baryogenesis. We developed a numerical code to study the real-time evolution of expanding bubbles and investigate how their walls reach stationary states. Our results agree with profiles obtained within the so-called bag model with very good accuracy, however, not all such solutions are stable and realised in dynamical systems. Depending on the exact shape of the potential there is always a range of wall velocities where no steady state solutions exist. This behaviour in deflagrations was explained by hydrodynamical obstruction where solutions that would heat the plasma outside the wall above the critical temperature and cause local symmetry restoration are forbidden. For even more affected hybrid solutions causes are less straight forward, however, we provide a simple numerical fit allowing one to verify if a solution with a given velocity is allowed simply by computing the ratio of the nucleation temperature to the critical one for the potential in question.

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T. Krajewski, M. Lewicki and M. Zych
Mon, 3 Apr 23
39/53

Comments: N/A

Maximal temperature of strongly-coupled dark sectors [CL]

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http://arxiv.org/abs/2303.17973


Taking axion inflation as an example, we estimate the maximal temperature ($T_{\rm max}^{ }$) that can be reached in the post-inflationary universe, as a function of the confinement scale of a non-Abelian dark sector ($\Lambda_{\rm IR}^{ }$). Below a certain threshold $\Lambda_{\rm IR}^{ } < \Lambda_{\rm 0}^{ } \sim 2\times 10^{-8}{ } m{\rm pl}^{ }$, the system heats up to $T_{\rm max}^{ } \sim \Lambda_{\rm 0}^{ } > T_{\rm c}^{ }$, and a first-order thermal phase transition takes place. On the other hand, if $\Lambda_{\rm IR}^{ } > \Lambda_{\rm 0}^{ }$, then $T_{\rm max}^{ } \sim \Lambda_{\rm IR}^{ } < T_{\rm c}^{ }$: very high temperatures can be reached, but there is no phase transition. If the inflaton thermalizes during heating-up (which we find to be unlikely), or if the plasma includes light degrees of freedom, then heat capacity and entropy density are larger, and $T_{\rm max}^{ }$ is lowered towards $\Lambda_{\rm 0}^{ }$. The heating-up dynamics generates a gravitational wave background. Its contribution to $N^{ }{\rm eff}$ at GHz frequencies, the presence of a monotonic $\sim f{\rm 0}^3$ shape at $(10^{-4}{ } – 10^2{ })\,$Hz frequencies, and the frequency domain of peaked features that may originate via first-order phase transitions, are discussed.

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H. Kolesova, M. Laine and S. Procacci
Mon, 3 Apr 23
43/53

Comments: 21 pages

The role of soft photon injection and heating in 21 cm cosmology [CEA]

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http://arxiv.org/abs/2303.17311


The ARCADE radio excess and EDGES measurement remain puzzling. A link between the two has been previously considered, however, in this work we highlight an important related effect that was not analyzed in detail before. By performing cosmological thermalization calculations with soft photon injection using {\tt CosmoTherm}, we show that for the 21 cm signal generation the interplay between enhanced radio spectral distortions and the associated heating can hide a significant radio excess before the reionzation era. We illustrate this effect for a simple power-law soft photon source in decaying particle scenarios. Even if simplistic, the uncovered link between CMB spectral distortions and 21 cm cosmology should apply to a much broader range of scenarios. This could significantly affect the constraints derived from existing and future 21 cm observations on the evolution of the ambient radio background. In particular, scenarios that would be ruled out by existing data without heating could become viable solutions once the heating is accounted for in the modelling. Our calculations furthermore highlight the importance of global 21 cm observations reaching into the dark ages, where various scenarios can potentially be distinguished.

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S. Acharya, B. Cyr and J. Chluba
Fri, 31 Mar 23
6/70

Comments: Comments welcome

Constraining ultralight dark matter using the Fermi-LAT Pulsar Timing Array [HEAP]

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http://arxiv.org/abs/2303.17545


Ultralight dark matter (ULDM) is proposed as a theoretical candidate of dark matter particles with masses of approximately $10^{-22}$ eV. The interactions between ULDM particles and standard model particles would cause variations in pulse arrival times of the pulsars, which makes the pulsar timing array (PTA) can be used to indirectly detect ULDM. In this work, we use the gamma-ray PTA composed of 29 millisecond pulsars observed by the Fermi Large Area Telescope (Fermi-LAT) to test four ultralight dark matter effects, including gravitational effects for generalized ULDM with different Spin-0/1, the fifth-force coupling effect of Dark Photon and the modified gravitational effect of the Spin-2 ULDM. The gamma-ray pulsar timing is not affected by the ionized interstellar medium and suffers relatively simple noises, unlike that of the radio band. No significant signals of ULDM are found based on the Fermi-LAT PTA for all four kinds of ULDM models. Constraints on ULDM parameters are set with the 95% confidence level, which provides a complementary check of the non-detection of ULDM for radio PTAs and direct detection experiments.

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Z. Xia, T. Tang, X. Huang, et. al.
Fri, 31 Mar 23
12/70

Comments: 9 pages, 4 figures, 2 tables

Theoretical and Experimental Constraints for the Equation of State of Dense and Hot Matter [CL]

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http://arxiv.org/abs/2303.17021


This review aims at providing an extensive discussion of modern constraints relevant for dense and hot strongly interacting matter. It includes theoretical first-principle results from lattice and perturbative QCD, as well as chiral effective field theory results. From the experimental side, it includes heavy-ion collision and low-energy nuclear physics results, as well as observations from neutron stars and their mergers. The validity of different constraints, concerning specific conditions and ranges of applicability, is also provided.

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R. Kumar, V. Dexheimer, J. Jahan, et. al.
Fri, 31 Mar 23
20/70

Comments: N/A

Fully inhomogeneous non-linear dynamics of axion inflation [CEA]

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http://arxiv.org/abs/2303.17436


We study the non-linear dynamics of axion inflation, capturing for the first time the inhomogeneity and full dynamical range, till the end of inflation. Accounting for inhomogeneous effects during backreaction leads to a number of new relevant results, compared to spatially homogeneous studies: {\it i)} the number of extra efoldings beyond slow roll inflation increases very rapidly with the coupling, {\it ii)} oscillations of the inflaton velocity are attenuated, {\it iii)} the tachyonic gauge field helicity spectrum is smoothed out (i.e.~the spectral oscillatory features disappear), broadened, and shifted to smaller scales, and {\it iv)} the non-tachyonic helicity is excited, reducing the chiral asymmetry, now scale dependent. Our results are expected to impact strongly on the phenomenology and observability of axion inflation, including gravitational wave generation and primordial black hole production.

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D. Figueroa, J. Lizarraga, A. Urio, et. al.
Fri, 31 Mar 23
25/70

Comments: 9 pages including Supplemental Material; 4 figures

Primordial black holes and stochastic inflation beyond slow roll: I — noise matrix elements [CEA]

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http://arxiv.org/abs/2303.17375


Primordial Black Holes (PBHs) may form in the early Universe, from the gravitational collapse of large density perturbations, generated by large quantum fluctuations during inflation. Since PBHs form from rare over-densities, their abundance is sensitive to the tail of the primordial probability distribution function (PDF) of the perturbations. It is therefore important to calculate the full PDF of the perturbations, which can be done non-perturbatively using the ‘stochastic inflation’ framework. In single field inflation models generating large enough perturbations to produce an interesting abundance of PBHs requires violation of slow roll. It is therefore necessary to extend the stochastic inflation formalism beyond slow roll. A crucial ingredient for this are the stochastic noise matrix elements of the inflaton potential. We carry out analytical and numerical calculations of these matrix elements for a potential with a feature which violates slow roll and produces large, potentially PBH generating, perturbations. We find that the transition to an ultra slow-roll phase results in the momentum induced noise terms becoming larger than the field noise whilst each of them falls exponentially for a few e-folds. The noise terms then start rising with their original order restored, before approaching constant values which depend on the nature of the slow roll parameters in the post transition epoch. This will significantly impact the quantum diffusion of the coarse-grained inflaton field, and hence the PDF of the perturbations and the PBH mass fraction.

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S. Mishra, E. Copeland and A. Green
Fri, 31 Mar 23
53/70

Comments: 47 pages, 8 figures

Constraining the dark matter contribution of $γ$ rays in Cluster of galaxies using Fermi-LAT data [HEAP]

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http://arxiv.org/abs/2303.16930


Clusters of galaxies are the largest gravitationally-bound systems in the Universe. Their dynamics are dominated by dark matter (DM), which makes them among the best targets for indirect DM searches. We analyze 12 years of data collected by the Fermi Large Area Telescope (Fermi-LAT) in the direction of 49 clusters of galaxies selected for their proximity to the Earth and their high X-ray flux, which makes them the most promising targets. We first create physically motivated models for the DM density around each cluster considering different assumptions for the substructure distribution. Then we perform a combined search for a $\gamma$-ray signal in the {\it Fermi}-LAT data between 500 MeV and 1 TeV. We find a signal of $\gamma$ rays potentially associated with DM that is at a statistical significance of $2.5\sigma-3.0\sigma$ when considering a slope for the subhalo mass distribution $\alpha=1.9$ and minimum mass of $M_{\rm{min}}=10^{-6}$ $M_{\odot}$. The best-fit DM mass and annihilation cross-sections for a $b\bar{b}$ annihilation channel are $m_{\chi}=40-60$ GeV and $\langle \sigma v \rangle = (2-4) \times 10^{-25}$ cm$^3$/s. When we consider $\alpha=2.0$ and $M_{\rm{min}}=10^{-9}$ $M_{\odot}$, the best-fit of the cross section reduces to $\langle \sigma v \rangle = (4-10) \times 10^{-26}$ cm$^3$/s. For both DM substructure models there is a tension between the values of $\langle \sigma v \rangle$ that we find and the upper limits obtained with the non-detection of a $\gamma$-ray flux from Milky Way dwarf spheroidal galaxies. This signal is thus more likely associated with $\gamma$ rays produced in the intracluster region by cosmic rays colliding with gas and photon fields.

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M. Mauro, J. Pérez-Romero, M. Sánchez-Conde, et. al.
Fri, 31 Mar 23
56/70

Comments: 27 Pages, 13 Figures. Accepted for publication in the PRD journal

T violation and the dark sector [CL]

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http://arxiv.org/abs/2303.16586


It is argued, as a working hypothesis, that “normal” and dark matter interactions can only be T and CP violating. One way to implement this idea is to consider that time reversal in dark matter is implemented, not by an antiunitary operator, but by a unitary operator. It is shown how this occurs naturally in the context of complex spacetime with an extended symmetry group.

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R. Mendes
Thu, 30 Mar 23
9/66

Comments: 6 pages Latex

Dynamically screened strongly quantized electron transport in binary neutron-star merger [CL]

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http://arxiv.org/abs/2303.16811


We examine electron-transport coefficients in magnetized hot and dense electron-ion plasma relevant in binary neutron star merger simulation. We calculate electrical and thermal conductivities in low density, high temperature, highly magnetized plasma of binary neutron star mergers where quantum oscillatory behavior of electrons emerge. For pronounced thermodynamic effects, we consider zeroth Landau level population of electrons for the calculation of conductivity. We solve Boltzmann equation in presence of magnetic field to obtain the dissipative components of electrical and thermal conductivities. The dissipative coefficients are formulated considering frequency dependent dynamical screening in the quantized electron-ion scattering rate. Numerical estimations show that the effect of dynamical screening of photon propagator on electrical and thermal conductivities is pronounced. We observe that dynamical screening reduces the maxima of both the electrical and thermal conductivities by factors of thirty one and twenty respectively leading to a reduction in the corresponding time scales of these coefficients. The common scaling factor between electrical and thermal conductivity is also observed to follow cubic relationship with temperature violating Wiedemann-Franz law.

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S. Sarkar and S. Adhya
Thu, 30 Mar 23
10/66

Comments: Accepted in The European Physical Journal C. arXiv admin note: substantial text overlap with arXiv:2108.11878

New Insight on Neutrino Dark Matter Interactions from Small-Scale CMB Observations [CEA]

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http://arxiv.org/abs/2303.16895


We revisit the possibility of using cosmological observations to constrain models that involve interactions between neutrinos and dark matter. We show that small-scale measurements of the cosmic microwave background with a few per cent accuracy are critical to uncover unique signatures from models with tiny couplings that would require a much higher sensitivity at lower multipoles, such as those probed by the Planck satellite. We analyze the high-multipole data released by the Atacama Cosmology Telescope, both independently and in combination with Planck and Baryon Acoustic Oscillation measurements, finding a compelling preference for a non-vanishing coupling, $\log_{10}u_{\nu \textrm{DM}}=-5.20^{+1.2}_{-0.74}$ at 68% CL. This aligns with other CMB-independent probes, such as Lyman-$\alpha$. We illustrate how this coupling could be accounted for in the presence of dark matter interactions with a sterile neutrino.

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P. Brax, C. Bruck, E. Valentino, et. al.
Thu, 30 Mar 23
15/66

Comments: 6 pages, 3 figures

Fast radio burst energy function in the presence of $\rm DM_{host}$ variation [HEAP]

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http://arxiv.org/abs/2303.16775


Fast radio bursts (FRBs) have been found in great numbers but the physical mechanism of these sources is still a mystery. The redshift evolutions of the FRB energy distribution function and the volumetric rate shed light on revealing the origin of the FRBs. However, such estimations rely on the dispersion measurement (DM)-redshift ($z$) relationship. A few of FRBs detected recently show large excess DM beyond the expectation from the cosmological and Milky Way contributions, which indicates large spread of DM from their host galaxies. In this work, we adopt the lognormal distributed $\rm DM_{host}$ model and estimate the energy function using the non-repeating FRBs selected from the Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB Catalog 1. By comparing the lognormal distributed $\rm DM_{host}$ model to the constant $\rm DM_{host}$ model, the FRB energy function results are consistent within the measurement uncertainty. We also estimate the volumetric rate of the non-repeating FRBs in three different redshift bins. The volumetric rate shows that the trend is consistent with the stellar-mass density redshift evolution. Since the lognormal distributed $\rm DM_{host}$ model increases the measurement errors, the inference of FRBs tracking the stellar-mass density is nonetheless undermined.

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Y. Li, J. Zou, J. Zhang, et. al.
Thu, 30 Mar 23
65/66

Comments: 8 pages, 5 figures

Direct searches for general dark matter-electron interactions with graphene detectors: Part I. Electronic structure calculations [CL]

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http://arxiv.org/abs/2303.15497


We develop a formalism to describe electron ejections from graphene-like targets by dark matter (DM) scattering for general forms of scalar and spin 1/2 DM-electron interactions and compare their applicability and accuracy within the density functional theory (DFT) and tight binding (TB) approaches. This formalism allows for accurate prediction of the daily modulation signal expected from DM in upcoming direct detection experiments employing graphene sheets as the target material. A key result is that the physics of the graphene sheet and that of the DM and the ejected electron factorise, allowing for the rate of ejections from all forms of DM to be obtained with a single graphene response function. We perform a comparison between the TB and DFT approaches to modeling the initial state electronic wavefunction within this framework, with DFT emerging as the more self-consistent and reliable choice due to the challenges in the embedding of an appropriate atomic contribution into the TB approach.

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R. Catena, T. Emken, M. Matas, et. al.
Wed, 29 Mar 23
6/73

Comments: 29 pages, 12 figures, 5 appendices. The TB and DFT codes can be found under this https URL and this https URL respectively

Anticipating the XRISM search for the decay of resonantly produced sterile neutrino dark matter [CEA]

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http://arxiv.org/abs/2303.15513


The resonantly produced sterile neutrino ($N_1$) of the neutrino minimal standard model ($\nu$MSM) is a compelling dark matter candidate, especially in the reported possible detection of $N_1$ with mass $m_\mathrm{s}=7.1$~keV in X-ray decay. This particle will be accessible to the XRISM X-ray mission over the next 12 months. We revisit the physics behind $N_1$ and the uncertainty in its parameters. We compare predictions for the $m_\mathrm{s}=7.1$keV $N_1$ mixing angle, $\sin^{2}(2\theta)$, and half-mode mass, $M_\mathrm{hm}$, to existing X-ray observations and structure formation constraints. The strongest available constraints rule out $N_1$ as a dark matter candidate, and a more optimistic reading of the data prefers $\sin^{2}(2\theta)=5\times10^{-11}$ and $M_\mathrm{hm}=3.5\times10^{8}$$\mathrm{M}_{\odot}$. We highlight that the most promising upcoming opportunity for a detection is to find a line of velocity dispersion $\sim500$$\mathrm{kms^{-1}}$ in the Virgo cluster with XRISM, and then draw up a list of future objects of study to determine: (i) whether the line is from dark matter generally, and (ii) if from dark matter, whether that candidate is indeed $N_1$.

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M. Lovell
Wed, 29 Mar 23
43/73

Comments: 13 pages, 7 figures. To be submitted to MNRAS. Contact: lovell@hi.is

Squeezed bispectrum and one-loop corrections in transient constant-roll inflation [CEA]

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http://arxiv.org/abs/2303.16035


In canonical single-field inflation, the production of primordial black holes (PBH) requires a transient violation of the slow-roll condition. The transient ultra slow-roll inflation is an example of such scenario, and more generally, one can consider the transient constant-roll inflation. We investigate the squeezed bispectrum in the transient constant-roll inflation, and find that the Maldacena’s consistency relation holds for a sufficiently long-wavelength mode, whereas it is violated for modes around the peak scale for the non-attractor case. We also demonstrate how the one-loop corrections are modified compared to the case of the transient ultra slow-roll inflation, focusing on representative one-loop terms orgiginating from a time derivative of the second slow-roll parameter in the cubic action. We find that the perturbativity requirement on those terms does not rule out the production of PBH from the transient constant-roll inflation. Therefore, it is a simple counterexample of the recently claimed no-go theorem of PBH production from single-field inflation.

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H. Motohashi and Y. Tada
Wed, 29 Mar 23
46/73

Comments: 26 pages, 14 figures

Scalar Love numbers and Love symmetries of 5-dimensional Myers-Perry black hole [CL]

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http://arxiv.org/abs/2303.16036


The near-zone “Love” symmetry resolves the naturalness issue of black hole Love number vanishing with $\text{SL}\left(2,\mathbb{R}\right)$ representation theory. Here, we generalize this proposal to $5$-dimensional asymptotically flat and doubly spinning (Myers-Perry) black holes. We consider the scalar response of Myers-Perry black holes and extract its static scalar Love numbers. In agreement with the naturalness arguments, these Love numbers are, in general, non-zero and exhibit logarithmic running unless certain resonant conditions are met; these conditions include new cases with no previously known analogs. We show that there exist two near-zone truncations of the equations of motion that exhibit enhanced $\text{SL}\left(2,\mathbb{R}\right)$ Love symmetries that explain the vanishing of the static scalar Love numbers in the resonant cases. These Love symmetries can be interpreted as local $\text{SL}\left(2,\mathbb{R}\right)\times\text{SL}\left(2,\mathbb{R}\right)$ near-zone symmetries spontaneously broken down to global $\text{SL}\left(2,\mathbb{R}\right)\times U\left(1\right)$ symmetries by the periodic identification of the azimuthal angles. We also discover an infinite-dimensional extension of the Love symmetry into $\text{SL}\left(2,\mathbb{R}\right)\ltimes\hat{U}\left(1\right)_{\mathcal{V}}^2$ that contains both Love symmetries as particular subalgebras, along with a family of $\text{SL}\left(2,\mathbb{R}\right)$ subalgebras that reduce to the exact near-horizon Myers-Perry black hole isometries in the extremal limit. Finally, we show that the Love symmetries acquire a geometric interpretation as isometries of subtracted (effective) black hole geometries that preserve the internal structure of the black hole and interpret these non-extremal $\text{SL}\left(2,\mathbb{R}\right)$ structures as remnants of the enhanced isometry of the near-horizon extremal geometries.

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P. Charalambous and M. Ivanov
Wed, 29 Mar 23
48/73

Comments: 45+16 pages, 3 Figures

Ultra-peripheral collisions of charged hadrons in extensive air showers [CL]

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http://arxiv.org/abs/2303.16042


We discuss the electromagnetic collisions of high energy protons, pions and kaons with atmospheric nuclei. In particular, we use the equivalent photon approximation to estimate (i) the diffractive collisions where the projectile scatters inelastically off a nucleus, and (ii) the usual radiative processes (bremsstrahlung, pair production and photonuclear interactions) of these charged hadrons in the air. We then include the processes in the simulator AIRES and study how they affect the longitudinal development of extensive air showers. For $10^{9-11}$ GeV proton primaries we find that they introduce a very small reduction (below 1%) in the average value of both $X_{\rm max}$ and $\Delta X_{\rm max}$. At a given shower age (relative slant depth from $X_{\rm max}$), these electromagnetic processes do not change significantly the number of muons or the total energy carried by electrons and photons, increased by just 1% the muon-to-($\gamma+e$) signal at the ground level.

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M. Masip, I. Rosario and S. Sciutto
Wed, 29 Mar 23
52/73

Comments: 14 pages

Universality of Cherenkov Light in EAS [HEAP]

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http://arxiv.org/abs/2303.15653


The reconstruction of cosmic-ray-induced extensive air showers with a non-imaging Cherenkov detector array requires knowledge of the Cherenkov yield of any given air shower for a given set of shower parameters. Although air showers develop in a stochastic cascade, certain characteristics of the particles in the shower have been shown to come from universal probability distributions, a property known as shower universality. Both the energy and the angular distributions of charged particles within a shower have been parameterized. One can use these distributions to calculate the Cherenkov photon yield as an angular distribution from the Cherenkov cones of charged particles at various stages of shower development. This Cherenkov photon yield can then be tabulated for use in the reconstruction of air showers. In this work, we develop the calculation of both the Cherenkov angular distribution and Cherenkov yield per shower particle, and show how a look-up table was constructed to capture the relevant features of these distributions for general use. We compare the results of our calculations with the results of full, particle-stack, Monte Carlo simulation of the Cherenkov light produced in extensive air showers using CORSIKA-IACT. We make comparisons of both the lateral distribution of the Cherenkov photon flux amongst several detectors and of the arrival-time distribution of the Cherenkov photons in a single detector.

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I. Buckland and D. Bergman
Wed, 29 Mar 23
60/73

Comments: N/A

Direct searches for general dark matter-electron interactions with graphene detectors: Part II. Sensitivity studies [CL]

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http://arxiv.org/abs/2303.15509


We use a formalism that describes electron ejections from graphene-like targets by dark matter (DM) scattering for general forms of scalar and spin 1/2 DM-electron interactions in combination with state-of-the-art density functional calculations to produce predictions and reach estimates for various possible carbon-based detector designs. Our results indicate the importance of a proper description of the target electronic structure. In addition, we find a strong dependence of the predicted observed signal for different DM candidate masses and interaction types on the detailed geometry and design of the detector. Combined with directional background vetoing, these dependencies will enable the identification of DM particle properties once a signal has been established.

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R. Catena, T. Emken, M. Matas, et. al.
Wed, 29 Mar 23
67/73

Comments: 22 pages, 15 figures, 2 appendices. The DFT code can be found under this https URL

Decay of ALP Condensates via Gravitation-Induced Resonance [CL]

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http://arxiv.org/abs/2303.14800


Oscillating scalar field condensates induce small amplitude oscillations of the Hubble parameter which can induce a decay of the condensate due to a parametric resonance instability [1]. We show that this instability can lead to the decay of the coherence of the condensate of axion-like particle (ALP) fields during the radiation phase of standard cosmology for rather generic ALP parameter values, with possible implications for certain experiments aiming to search for ALP candidates. As an example, we study the application of this instability to the QCD axion. We also study the magnitude of the induced entropy fluctuations.

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R. Brandenberger, V. Kamali and R. Ramos
Tue, 28 Mar 23
37/81

Comments: 9 pages, 2 figures

Constraint on Early Dark Energy from Isotropic Cosmic Birefringence [CEA]

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http://arxiv.org/abs/2303.15369


Polarization of the cosmic microwave background (CMB) is sensitive to new physics violating parity symmetry, such as the presence of a pseudoscalar “axionlike” field. Such a field may be responsible for early dark energy (EDE), which is active prior to recombination and provides a solution to the so-called Hubble tension. The EDE field coupled to photons in a parity-violating manner would rotate the plane of linear polarization of the CMB and produce a cross-correlation power spectrum of $E$- and $B$-mode polarization fields with opposite parities. In this paper, we fit the $EB$ power spectrum predicted by the photon-axion coupling of the EDE model with a potential $V(\phi)\propto [1-\cos(\phi/f)]^3$ to polarization data from Planck. We find that the unique shape of the predicted $EB$ power spectrum is not favored by the data and obtain a first constraint on the photon-axion coupling constant, $g=(0.04\pm 0.16)M_{\text{Pl}}^{-1}$ (68% CL), for the EDE model that best fits the CMB and galaxy clustering data. This constraint is independent of the miscalibration of polarization angles of the instrument or the polarized Galactic foreground emission. Our limit on $g$ may have important implications for embedding EDE in fundamental physics, such as string theory.

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J. Eskilt, L. Herold, E. Komatsu, et. al.
Tue, 28 Mar 23
47/81

Comments: 7 pages, 3 figures, 1 table. The stacked EB power spectrum is publicly available at this https URL

Exploring QCD matter in extreme conditions with Machine Learning [CL]

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http://arxiv.org/abs/2303.15136


In recent years, machine learning has emerged as a powerful computational tool and novel problem-solving perspective for physics, offering new avenues for studying strongly interacting QCD matter properties under extreme conditions. This review article aims to provide an overview of the current state of this intersection of fields, focusing on the application of machine learning to theoretical studies in high energy nuclear physics. It covers diverse aspects, including heavy ion collisions, lattice field theory, and neutron stars, and discuss how machine learning can be used to explore and facilitate the physics goals of understanding QCD matter. The review also provides a commonality overview from a methodology perspective, from data-driven perspective to physics-driven perspective. We conclude by discussing the challenges and future prospects of machine learning applications in high energy nuclear physics, also underscoring the importance of incorporating physics priors into the purely data-driven learning toolbox. This review highlights the critical role of machine learning as a valuable computational paradigm for advancing physics exploration in high energy nuclear physics.

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K. Zhou, L. Wang, L. Pang, et. al.
Tue, 28 Mar 23
59/81

Comments: 146 pages,53 figures

First Dark Matter Search with Nuclear Recoils from the XENONnT Experiment [CL]

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http://arxiv.org/abs/2303.14729


We report on the first search for nuclear recoils from dark matter in the form of weakly interacting massive particles (WIMPs) with the XENONnT experiment which is based on a two-phase time projection chamber with a sensitive liquid xenon mass of $5.9$~t. During the approximately 1.1 tonne-year exposure used for this search, the intrinsic $^{85}$Kr and $^{222}$Rn concentrations in the liquid target were reduced to unprecedentedly low levels, giving an electronic recoil background rate of $(15.8\pm1.3)~\mathrm{events}/(\mathrm{t\cdot y \cdot keV})$ in the region of interest. A blind analysis of nuclear recoil events with energies between $3.3$~keV and $60.5$~keV finds no significant excess. This leads to a minimum upper limit on the spin-independent WIMP-nucleon cross section of $2.58\times 10^{-47}~\mathrm{cm}^2$ for a WIMP mass of $28~\mathrm{GeV}/c^2$ at $90\%$ confidence level. Limits for spin-dependent interactions are also provided. Both the limit and the sensitivity for the full range of WIMP masses analyzed here improve on previous results obtained with the XENON1T experiment for the same exposure.

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X. Collaboration, E. Aprile, K. Abe, et. al.
Tue, 28 Mar 23
60/81

Comments: Limit points are included in the submission file

The Invisible Dilaton [CL]

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http://arxiv.org/abs/2303.14469


We analyse the dynamics of a light scalar field responsible for the $\mu$ term of the Higgs potential and coupled to matter via the Higgs-portal mechanism. We find that this dilaton model is stable under radiative corrections induced by the standard model particle masses. When the background value of the scalar field is stabilised at the minimum of the scalar potential, the scalar field fluctuations only couple quadratically to the massive fields of the standard model preventing the scalar direct decay into standard model particles. Cosmologically and prior to the electroweak symmetry breaking, the scalar field rolls down along its effective potential before eventually oscillating and settling down at the electroweak minimum. These oscillations can be at the origin of dark matter due to the initial misalignment of the scalar field compared to the electroweak minimum, and we find that, when the mass of the scalar field is less than the eV scale and acts as a condensate behaving like dark matter on large scales, the scalar particles cannot thermalise with the standard model thermal bath. As matter couples in a composition-dependent manner to the oscillating scalar, this could lead to a violation of the equivalence principle aboard satellites such as the MICROSCOPE experiment and the next generation of tests of the equivalence principle. Local gravitational tests are evaded thanks to the weakness of the quadratic coupling in the dark matter halo, and we find that, around other sources, these dilaton models could be subject to a screening akin to the symmetron mechanism.

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P. Brax, C. Burrage, J. Cembranos, et. al.
Tue, 28 Mar 23
74/81

Comments: 36 pages, 3 figures

Search for neutrino lines from dark matter annihilation and decay with IceCube [HEAP]

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http://arxiv.org/abs/2303.13663


Dark Matter particles in the Galactic Center and halo can annihilate or decay into a pair of neutrinos producing a monochromatic flux of neutrinos. The spectral feature of this signal is unique and it is not expected from any astrophysical production mechanism. Its observation would constitute a dark matter smoking gun signal. We performed the first dedicated search with a neutrino telescope for such signal, by looking at both the angular and energy information of the neutrino events. To this end, a total of five years of IceCube’s DeepCore data has been used to test dark matter masses ranging from 10~GeV to 40~TeV. No significant neutrino excess was found and upper limits on the annihilation cross section, as well as lower limits on the dark matter lifetime, were set. The limits reached are of the order of $10^{-24}$~cm$^3/s$ for an annihilation and up to $10^{27}$ seconds for decaying Dark Matter. Using the same data sample we also derive limits for dark matter annihilation or decay into a pair of Standard Model charged particles.

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I. Collaboration, R. Abbasi, M. Ackermann, et. al.
Mon, 27 Mar 23
3/59

Comments: N/A

New Resonances of Supernova Neutrinos in Twisting Magnetic Fields [CL]

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http://arxiv.org/abs/2303.13572


We investigate the effect of resonant spin conversion of the neutrinos induced by the geometrical phase in a twisting magnetic field. We find that the geometrical phase originating from the rotation of the transverse magnetic field along the neutrino trajectory can trigger a new resonant spin conversion of Dirac neutrinos inside the supernova, even if there were no such transitions in the fixed-direction field case. We have shown that even though resonant spin conversion is too weak to affect solar neutrinos, it could have a remarkable consequence on supernova neutronization bursts where very intense magnetic fields are quite likely. We demonstrate how the flavor composition at Earth can be used as a probe to establish the presence of non-negligible magnetic moments, potentially down to $10^{-15}~\mu_B$ in upcoming neutrino experiments like the Deep Underground Neutrino Experiment (DUNE), and the Hyper-Kamiokande (HK). Possible implications are analyzed.

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S. Jana and Y. Porto
Mon, 27 Mar 23
7/59

Comments: 5 pages + references, 3 figures

Reviewing the prospect of fermion triplets as dark matter and source of baryon asymmetry in non-standard cosmology [CL]

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http://arxiv.org/abs/2303.13950


The indirect searches of Dark Matter (DM), in conjugation with the so called `missing track searches’ at the collider seems to confine fermion triplet DM mass within a narrow range around 1 TeV. The canonical picture of pure triplet fermionic DM is in tension since it is under-abundant for the said mass range. Several preceding studies have shown that the existence of an extra species over the radiation background, prior to the Big Bang Nucleosynthesis, leads to a fast expanding Universe driven by an enhanced Hubble parameter. This faster (than radiation) expansion has the potential to revive the under-abundant fermion triplet ($\mathbb{Z}_2$ odd) WIMP dark matter scenario by causing freeze-out earlier without modifying the interaction strength between DM and thermal bath. Although the CP asymmetry, produced due to the decay of $\mathbb{Z}_2$ even heavier generations of the triplet, remains unaffected by the modification of cosmology, the evolution of the same receives significant non-trivial effect. It has been observed through numerical estimations that the minimum mass of the decaying triplet, required to produce sufficient baryon asymmetry, can be lowered up to two orders (compared to the standard cosmology) in this fast expansion scenario. The non-standard parameters $n$ and $T_r$, which simultaneously control the DM relic abundance as well the frozen value of baryon asymmetry, are tightly constrained due to consecutive imposition of experimental bounds on relic density followed by observed value of baryon asymmetry of the Universe. It has been found that $n$ is strictly bounded within the interval $0.4\lesssim n \lesssim 1.6$. The upper bound is imposed by the baryon asymmetry constraint whereas the lower bound arises to satisfy the correct relic abundance of the DM. The restriction on $T_r$ is not so stringent as it can vary from sub GeV to few tens of GeV.

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A. Biswas, M. Chakraborty and S. Khan
Mon, 27 Mar 23
11/59

Comments: 39 pages, 10 figures, 1 table

Borexino's search for low-energy neutrinos associated with gravitational wave events from GWTC-3 database [HEAP]

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http://arxiv.org/abs/2303.13876


The search for neutrino events in correlation with gravitational wave (GW) events for three observing runs (O1, O2 and O3) from 09/2015 to 03/2020 has been performed using the Borexino data-set of the same period. We have searched for signals of neutrino-electron scattering with visible energies above 250 keV within a time window of 1000 s centered at the detection moment of a particular GW event. Two types of incoming neutrino spectra were considered: the mono-energetic line and the spectrum expected from supernovae. The same spectra were considered for electron antineutrinos detected through inverse beta-decay (IBD) reaction. GW candidates originated by merging binaries of black holes (BHBH), neutron stars (NSNS) and neutron star and black hole (NSBH) were analysed separately. In total, follow-ups of 74 out of 93 gravitational waves reported in the GWTC-3 catalog were analyzed and no statistically significant excess over the background was observed. As a result, the strongest upper limits on GW-associated neutrino and antineutrino fluences for all flavors (\nu_e, \nu_\mu, \nu_\tau) have been obtained in the (0.5 – 5.0) MeV neutrino energy range.

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B. Basilico, G. Bellini, J. Benziger, et. al.
Mon, 27 Mar 23
12/59

Comments: 13 pages, 8 figures

Primordial black hole dark matter from catastrogenesis with unstable pseudo-Goldstone bosons [CL]

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http://arxiv.org/abs/2303.14107


We propose a new scenario for the formation of asteroid-mass primordial black holes (PBHs). Our mechanism is based on the annihilation of the string-wall network associated with the breaking of a $U(1)$ global symmetry into a discrete $Z_N$ symmetry. If the potential has multiple local minima ($N>1$) the network is stable, and the annihilation is guaranteed by a bias among the different vacua. The collapse of the string-wall network is accompanied by catastrogenesis, a large production of pseudo-Goldstone bosons (pGBs) — e.g. axions, ALPs, or majorons — gravitational waves, and PBHs. If pGBs rapidly decay into products that thermalize, as predicted e.g. in the high-quality QCD axion and heavy majoron models, they do not contribute to the dark matter population, but we show that PBHs can constitute 100% of the dark matter. The gravitational wave background produced by catastrogenesis with heavy unstable axions, ALPs, or majorons could be visible in future interferometers.

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G. Gelmini, J. Hyman, A. Simpson, et. al.
Mon, 27 Mar 23
19/59

Comments: 24 pages, 4 figures

Multipole vector dark matter below the GeV-scale [CL]

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http://arxiv.org/abs/2303.13643


We consider electrically neutral complex vector particles $V$ below the GeV mass scale that, from a low energy perspective, couple to the photon via higher dimensional form factor interactions. We derive ensuing astrophysical constraints by considering the anomalous energy loss from the Sun, Horizontal Branch, and Red Giant stars as well as from SN1987A that arise from vector pair-production in these environments. Under the assumption that the dark states $V$ constitute dark matter, the bounds are then complemented by direct and indirect detection as well as cosmological limits. The relic density from freeze-out and freeze-in mechanisms is also computed. On the basis of a UV-complete model that realizes the considered effective couplings, we also discuss the naturalness of the constrained parameter space, and provide an analysis of the zero mass limit of $V$.

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X. Chu, J. Hisano, A. Ibarra, et. al.
Mon, 27 Mar 23
20/59

Comments: 15 pages, 3 figures

SKA sensitivity for possible radio emission from dark matter in Omega Centauri [HEAP]

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http://arxiv.org/abs/2303.14117


Omega Centauri, the largest known globular cluster in the Milky Way, is believed to be the remains of a dwarf galaxy’s core. Giving its potential abundance of dark matter (DM), it is an attractive target for investigating the nature of this elusive substance in our local environment. Our study demonstrates that by observing Omega Centauri with the SKA for 1000 hours, we can detect synchrotron radio or Inverse Compton (IC) emissions from the DM annihilation products. It enables us to constrain the cross-section of DM annihilation down to $\sim {\rm 10^{-30}~cm^3~s^{-1}}$ for DM mass from several $\rm{GeV}$ to $\rm{100~GeV}$, which is much stronger compared with other observations. Additionally, we explore the axion, another well-motivated DM candidate, and provide stimulated decay calculations. It turns out that the sensitivity can reach $g_{\rm{a\gamma\gamma}} \sim 10^{-10} ~\rm{GeV^{-1}}$ for $2\times 10^{-7} ~\rm{eV} < m_a < 2\times 10^{-4} ~\rm{eV}$.

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G. Wang, Z. Chen, L. Zu, et. al.
Mon, 27 Mar 23
24/59

Comments: 19 pages, 8 figures

Non-Gaussianity in rapid-turn multi-field inflation [CEA]

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http://arxiv.org/abs/2303.14156


We show that theories of inflation with multiple, rapidly turning fields can generate large amounts of non-Gaussianity. We consider a general theory with two fields, an arbitrary field-space metric, and a potential that supports sustained, rapidly turning field trajectories. Our analysis accounts for non-zero field cross-correlation and does not fix the power spectra of curvature and isocurvature perturbations to be equal at horizon crossing. Using the $\delta N$ formalism, we derive a novel, analytical formula for bispectrum generated from multi-field mixing on super-horizon scales. Rapid-turn inflation can produce a bispectrum with several potentially large contributions that are not necessarily of the local shape. We exemplify the applicability of our formula with a fully explicit model and show that the new contributions indeed can generate a large amplitude of local non-Gaussianity, $f_{\rm NL}^{\rm loc}\sim {\cal O}(1)$. These results will be important when interpreting the outcomes of future observations.

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O. Iarygina, M. Marsh and G. Salinas
Mon, 27 Mar 23
28/59

Comments: 35 pages, 6 figures

Inferring astrophysical neutrino sources from the Glashow resonance [CL]

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http://arxiv.org/abs/2303.13706


We infer the ultrahigh energy neutrino source by using the Glashow resonance candidate event recently identified by the IceCube Observatory. For the calculation of the cross section for the Glashow resonance, we incorporate both the atomic Doppler broadening effect and initial state radiation $\overline{\nu}^{}{e} e^- \to W^- \gamma$, which correct the original cross section considerably. Using available experimental information, we have set a generic constraint on the $\overline{\nu}^{}{e}$ fraction of astrophysical neutrinos, which excludes the $\mu$-damped ${\rm p}\gamma$ source around $2\sigma$ confidence level. While a weak preference has been found for the pp source, next-generation measurements will be able to distinguish between ideal pp and p$\gamma$ sources with a high significance assuming an optimistic single power-law neutrino spectrum.

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G. Huang, M. Lindner and N. Volmer
Mon, 27 Mar 23
42/59

Comments: 10 pages, 4 figures

Primordial feature constraints from BOSS+eBOSS [CEA]

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http://arxiv.org/abs/2303.13946


Understanding the universe in its pristine epoch is crucial in order to obtain a concise comprehension of the late-time universe. Although current data in cosmology are compatible with Gaussian primordial perturbations whose power spectrum follows a nearly scale-invariant power law, this need not be the case when a fundamental theoretical construction is assumed. These extended models lead to sharp features in the primordial power spectrum, breaking its scale invariance. In this work, we obtain combined constraints on four primordial feature models by using the final data release of the BOSS galaxies and eBOSS quasars. By pushing towards the fundamental mode of these surveys and using the larger eBOSS volume, we were able to extend the feature parameter space (i.e. the feature frequency $\omega$) by a factor of four compared to previous analyses using BOSS. While we did not detect any significant features, we show that next-generation galaxy surveys such as DESI will improve the sensitivity to features by a factor of 7, and will also extend the parameter space by a factor of 2.5.

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T. Mergulhão, F. Beutler and J. Peacock
Mon, 27 Mar 23
50/59

Comments: 28 + 4 pages, 16 figures

Gamma-rays and neutrinos from supernovae of Type Ib/c with late time emission [HEAP]

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http://arxiv.org/abs/2303.13576


Observations of some supernovae (SNe), such as SN 2014C, in the X-ray and radio wavebands revealed a rebrightening over a timescale of about a year since their detection. Such a discovery hints towards the evolution of a hydrogen-poor SN of Type Ib/c into a hydrogen-rich SN of Type IIn, the late time activity being attributed to the interaction of the SN ejecta with a dense hydrogen-rich circumstellar medium (CSM) far away from the stellar core. We compute the neutrino and gamma-ray emission from these SNe, considering interactions between the shock accelerated protons and the non-relativistic CSM protons. Assuming three CSM models inspired by recent electromagnetic observations, we explore the dependence of the expected multi-messenger signals on the CSM characteristics. We also investigate the detection prospects of current and upcoming gamma-ray (Fermi-LAT and Cerenkov Telescope Array) and neutrino (IceCube, IceCube-Gen2 and KM3NeT) telescopes. Our findings are in agreement with the non-detection of neutrinos and gamma-rays from past SNe exhibiting late time emission. Nevertheless, the detection prospects of SNe with late time emission in gamma-rays and neutrinos with the Cerenkov Telescope Array and IceCube-Gen2 (Fermi and IceCube) are promising and could potentially provide new insight into the CSM properties, if the SN burst should occur within $10$ Mpc ($4$ Mpc).

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P. Sarmah, S. Chakraborty, I. Tamborra, et. al.
Mon, 27 Mar 23
58/59

Comments: 9 pages, 4 figures

Upper limit on scalar field dark matter from LIGO-Virgo third observation run [CL]

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http://arxiv.org/abs/2303.13088


If dark matter is a light scalar field weakly interacting with elementary particles, such a field induces oscillations of the physical constants, which results in time-varying force acting on macroscopic objects. In this paper, we report on a search for such a signal in the data of the two LIGO detectors during their third observing run (O3). We focus on the mass of the scalar field in the range of $10^{-13}-10^{-11}~{\rm eV}$ for which the signal falls within the detectors’ sensitivity band. We first formulate the cross-correlation statistics that can be readily compared with publically available data. It is found that inclusion of the anisotropies of the velocity distribution of dark matter caused by the motion of the solar system in the Milky Way Galaxy enhances the signal by a factor of $\sim 2$ except for the narrow mass range around $\simeq 3\times 10^{-13}~{\rm eV}$ for which the correlation between the interferometer at Livingston and the one at Hanford is suppressed. From the non-detection of the signal, we derive the upper limits on the coupling constants between the elementary particles and the scalar field for five representative cases. For all the cases where the weak equivalence principle is not satisfied, tests of the violation of the weak equivalence principle provide the tightest upper limit on the coupling constants. Upper limits from the fifth-force experiment are always stronger than the ones from LIGO, but the difference is less than a factor of $\sim 5$ at large-mass range. Our study demonstrates that gravitational-wave experiments are starting to bring us meaningful information about the nature of dark matter. The formulation provided in this paper may be applied to the data of upcoming experiments as well and is expected to probe much wider parameter range of the model.

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K. Fukusumi, S. Morisaki and T. Suyama
Fri, 24 Mar 23
4/56

Comments: 21 pages, 5 figures

A flashing beacon in axion inflation: recurring bursts of gravitational waves in the strong backreaction regime [CEA]

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http://arxiv.org/abs/2303.13425


The coupling between a pseudo-scalar inflaton and a gauge field leads to an amount of additional density perturbations and gravitational waves (GWs) that is strongly sensitive to the inflaton speed. This naturally results in enhanced GWs at (relatively) small scales that exited the horizon well after the CMB ones, and that can be probed by a variety of GW observatories (from pulsar timing arrays, to astrometry, to space-borne and ground-based interferometers). This production occurs in a regime in which the gauge field significantly backreacts on the inflaton motion. Contrary to earlier assumptions, it has been recently shown that this regime is characterized by an oscillatory behavior of the inflaton speed, with a period of~${\rm O } \left( 5 \right)$ e-folds. Bursts of GWs are produced at the maxima of the speed, imprinting nearly periodic bumps in the frequency-dependent spectrum of GWs produced during inflation. This can potentially generate correlated peaks appearing in the same or in different GWs experiments.

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J. Garcia-Bellido, A. Papageorgiou, M. Peloso, et. al.
Fri, 24 Mar 23
6/56

Comments: 32 pages, 6 figures, link to an animation of the results: this https URL

LiteBIRD and CMB-S4 Sensitivities to Reheating in Plateau Models of Inflation [CL]

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http://arxiv.org/abs/2303.13503


We study the sensitivity of LiteBIRD and CMB-S4 to the reheating temperature and the inflaton coupling in three types of plateau-potential models of inflation, namely mutated hilltop inflation, radion gauge inflation, and $\alpha$-attractor T models. We first study the relations between model parameters and CMB observables in all models analytically. We then perform Monte Carlo Markov Chain based forecasts to quantify the information gain on the reheating temperature, the inflaton coupling, and the scale of inflation that can be achieved with LiteBIRD and CMB-S4. We compare the results of the forecasts to those obtained from a recently proposed simple analytic method. We find that both LiteBIRD and CMB-S4 can simultaneously constrain the scale of inflation and the reheating temperature in all three types of models. They can for the first time obtain both an upper and lower bound on the latter, comprising the first ever measurement. In the mutated hilltop inflation and radion gauge inflation models this can be translated into a measurement of the inflaton coupling in parts of the parameter space. Constraining this microphysical parameter will help to understand how these models of inflation may be embedded into a more fundamental theory of particle physics.

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M. Drewes, L. Ming and I. Oldengott
Fri, 24 Mar 23
9/56

Comments: 46 pages plus appendices, 43 figures

On the oscillations of the inflaton field of the simplest $α$-attractor T-model [CL]

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http://arxiv.org/abs/2303.13008


In this work, we consider homogeneous oscillations of the inflaton field after inflation. In particular, we obtain an analytical result for the (average) equation of state for the oscillating inflaton field for the simplest $\alpha$-attractor T-model. The result is useful for the study of its post-inflationary evolution. The most dramatic possibility is that during inflaton field oscillation, the (average) equation of state is that of a cosmological constant. This implies the end of slow-roll inflation in this model could be the beginning of oscillating inflation.

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C. Lin
Fri, 24 Mar 23
17/56

Comments: 9 pages, 3 figures

Resonant neutrino self-interactions and the $H_0$ tension [CEA]

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http://arxiv.org/abs/2303.12792


In this work, we study the previously unexplored resonant region of neutrino self-interactions. Current disagreement on late and early time observations of the Universe expansion could be solved with new physics acting before the recombination era. Nonstandard neutrino self-interactions are among the most appealing candidates to solve this issue since they could be testable in the near (or middle) future. We use linear cosmological datasets to test neutrino self-interactions for a sample of fixed scalar mediator masses in the range $10^{-2}$ eV $\leq m_{\varphi}\leq 10^{2}$ eV. The resonant behavior produces observable effects at lower couplings than those reported in the literature for heavy and light mediators. We observe that in the best case scenario, using the Planck + BAO dataset, the tension with local measurements of $H_0$ eases from 4.9$\sigma$ (for $\Lambda$CDM) down to 2.8$\sigma$. The joint data set which includes Planck, BAO, and $H_0$ prefers a non-zero interaction with at least 2.3$\sigma$ significance in the range $0.5$ eV $\leq m_{\varphi}\leq 10$ eV. These results add the last piece in the parameter space of neutrino self-interactions at the linear perturbation regime.

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J. Venzor, G. Garcia-Arroyo, A. Pérez-Lorenzana, et. al.
Thu, 23 Mar 23
5/67

Comments: N/A

Dark Matter spikes around Sgr A* in $γ$-rays [CL]

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http://arxiv.org/abs/2303.12107


We use H.E.S.S. $\gamma$-ray observations of Sgr A* to derive novel limits on the Dark Matter (DM) annihilation cross-section. We quantify their dependence on uncertainties i) in the DM halo profile, which we vary from peaked to cored, and ii) in the shape of the DM spike around Sgr A*, dynamically heated by the nuclear star cluster. For peaked halo profiles and depending on the heating of the spike, our limits are the strongest existing ones for DM masses above a few TeV. Our study contributes to assessing the influence of the advancements in our knowledge of the Milky Way on determining the properties of DM particles.

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S. Balaji, D. Sachdeva, F. Sala, et. al.
Thu, 23 Mar 23
13/67

Comments: 19 pages, 6 figures

Do the CMB Temperature Fluctuations Conserve Parity? [CEA]

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http://arxiv.org/abs/2303.12106


Observations of the Cosmic Microwave Background (CMB) have cemented the notion that the large-scale Universe is both statistically homogeneous and isotropic. But is it invariant also under mirror reflections? To probe this we require parity-sensitive statistics: for scalar observables, the simplest is the four-point function. We make the first measurements of the parity-odd CMB trispectrum, focusing on the large-scale ($2<\ell<510$) temperature anisotropies measured by Planck. This is facilitated by new maximum-likelihood estimators for binned correlators, which account for mask convolution and leakage between even- and odd-parity components, and achieve optimal variances within $\approx 20\%$. We perform a blind test for parity violation by comparing a $\chi^2$ statistic from Planck to theoretical expectations, using two suites of simulations to account for the possible likelihood non-Gaussianity and residual foregrounds. We find consistency at the $\approx 0.5\sigma$ level, yielding no evidence for parity violation, with roughly $250\times$ the squared sensitivity of large scale structure measurements (according to mode-counting arguments), and with the advantage of linear physics, Gaussian statistics, and accurate mocks. The measured trispectra can be used to constrain physical models of inflationary parity violation, including Ghost Inflation, Cosmological Collider scenarios, and Chern-Simons gauge fields. Considering eight such models, we find no evidence for new physics, with a maximal detection significance of $2.0\sigma$. These results suggest that the recent parity excesses seen in the BOSS galaxy survey are not primordial in origin. Tighter constraints can be wrought by including smaller scales (though rotational invariance washes out the flat-sky limit) and adding polarization data.

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O. Philcox
Thu, 23 Mar 23
16/67

Comments: 7+12 pages, 4+5 figures, submitted to Phys. Rev. Lett. Code available at this https URL

All-sky limits on Sterile Neutrino Galactic Dark Matter obtained with SRG/ART-XC after two years of operations [HEAP]

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http://arxiv.org/abs/2303.12673


Dark matter sterile neutrinos radiatively decay in the Milky Way, which can be tested with searches for almost monochromatic photons in the X-ray cosmic spectrum. We analyse the data of ART-XC telescope operated for two years in the all-sky survey mode. With no significant hints in the Galactic diffuse X-ray spectrum we explore models with sterile neutrino masses in 12-40 keV range and exclude corresponding regions of sterile-active neutrino mixing.

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E. Zakharov, V. Barinov, R. Burenin, et. al.
Thu, 23 Mar 23
48/67

Comments: 5 pages, 5 figures

Flavor solitons in dense neutrino gases [CL]

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http://arxiv.org/abs/2303.12143


We consider a dense neutrino gas in the “fast-flavor limit” (vanishing neutrino masses). For the first time, we identify exact solutions of the nonlinear wave equation in the form of solitons. They can propagate with both sub- or superluminal speed, the latter not violating causality. The soliton with infinite speed is a homogeneous solution and coincides with the usual fast-flavor pendulum except that it swings only once instead of being periodic. The subluminal soliton in the static limit corresponds to a one-swing “spatial pendulum”. A necessary condition for such solutions to exist is a “crossed” neutrino angle distribution. Based on the Nyquist criterion, we derive a new sufficient condition without solving the dispersion relation. The solitons are very fragile: they are as unstable as the homogeneous neutrino gas alone. Moreover, in the presence of matter, only the solution survives that is homogeneous in a frame comoving with the matter current. Generally, the matter effect cannot be eliminated by transformations in flavor space, but instead has a real physical impact.

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D. Fiorillo and G. Raffelt
Thu, 23 Mar 23
53/67

Comments: 12 pages, 8 figures, plus appendices

Dark Exoplanets [EPA]

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http://arxiv.org/abs/2303.12129


The prevailing assumption is that all exoplanets are made of ordinary matter. However, we propose an unconventional possibility that some exoplanets could be made of dark matter, which we name “dark exoplanets.” In this paper, we explore methods to search for dark exoplanets, including the mass-radius relation, spectroscopy, missing transit, and transit light curve. Specifically, we focus on the transit light curve method and demonstrate how to distinguish partially transparent dark exoplanets from fully opaque ordinary exoplanets using both observed exoplanet data and dark exoplanet mock data. Our analysis shows that dark exoplanets with a large radius (above around 10% of the star radius) and a small optical depth (below around one) can be identified with current telescope sensitivities.

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Y. Bai, S. Lu and N. Orlofsky
Thu, 23 Mar 23
66/67

Comments: 23 pages, 9 figures

The Strong Force meets the Dark Sector: a robust estimate of QCD uncertainties for anti-matter dark matter searches [CL]

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http://arxiv.org/abs/2303.11363


In dark-matter annihilation channels to hadronic final states, stable particles — such as positrons, photons, antiprotons, and antineutrinos — are produced via complex sequences of phenomena including QED/QCD radiation, hadronisation, and hadron decays. These processes are normally modelled by Monte Carlo event generators whose limited accuracy imply intrinsic QCD uncertainties on the predictions for indirect-detection experiments like Fermi-LAT, Pamela, IceCube or AMS-02. In this article, we perform a complete analysis of QCD uncertainties in antimatter spectra from dark-matter annihilation, based on parametric variations of the Pythia 8 event generator. After performing several retunings of light-quark fragmentation functions, we define a set of variations that span a conservative estimate of the QCD uncertainties. We estimate the effects on antimatter spectra for various annihilation channels and final-state particle species, and discuss their impact on fitted values for the dark-matter mass and thermally-averaged annihilation cross section. We find dramatic impacts which can go up to $\mathcal{O}(40)$ GeV for uncertainties on the dark-matter mass and up to $\mathcal{O}(10\%)$ for the annihilation cross section. We provide the spectra in tabulated form including QCD uncertainties and code snippets to perform fast dark-matter fits, in this https://github.com/ajueid/qcd-dm.github.io.git repository.

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A. Jueid, J. Kip, R. Austri, et. al.
Wed, 22 Mar 23
3/68

Comments: v1: 52 pages, 21 figures, and 9 tables

One-loop Corrections in Power Spectrum in Single Field Inflation [CEA]

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http://arxiv.org/abs/2303.12025


We revisit the one-loop correction in curvature perturbation power spectrum in models of single field inflation which undergo a phase of ultra slow-roll (USR) inflation. We include the contributions from both the cubic and quartic interaction Hamiltonians and calculate the one-loop corrections on the spectrum of the CMB scale modes from the small scale modes which leave the horizon during the USR phase. It is shown that the amplitude of one-loop corrections depends on the sharpness of the transition from the USR phase to the final slow-roll phase. For an arbitrarily sharp transition, the one-loop correction becomes arbitrarily large, invalidating the perturbative treatment of the analysis. We speculate that for a mild transition, the large one-loop corrections are washed out during the subsequent evolution after the USR phase. The implications for primordial black holes formation are briefly reviewed.

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H. Firouzjahi
Wed, 22 Mar 23
14/68

Comments: 26 pages, 1 Figure

Limits on Dark Matter Annihilation from the Shape of Radio Emission in M31 [CL]

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http://arxiv.org/abs/2303.11354


Well-motivated scenarios of thermally-produced dark matter often result in a population of electrons and positrons within galaxies produced through dark matter annihilation — often in association with high-energy gamma rays. As they diffuse through galactic magnetic fields, these $e^\pm$ produce synchrotron radio emission. The intensity and morphology of this signal depends on the properties of the interstellar medium through which the $e^\pm$ propagate. Using observations of the Andromeda Galaxy (M31) to construct a model of the gas, magnetic fields, and starlight, we set constraints on dark matter annihilation to $b\bar{b}$ using the morphology of 3.6 cm radio emission. As the emission signal at the center of M31 is very sensitive to the diffusion coefficient and dark matter profile, we base our limits on the differential flux in the region between $0.9-6.9$ kpc from the center. We exclude annihilation cross sections $\gtrsim 3 \times 10^{-25}$ cm$^3$/s in the mass range $10-500$ GeV, with a maximum sensitivity of $7\times 10^{-26}$ cm$^3$/s at $20-40$ GeV. Though these limits are weaker than those found in previous studies of M31, they are robust to variations of the diffusion coefficient.

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M. Weikert and M. Buckley
Wed, 22 Mar 23
20/68

Comments: 34 pages, 27 figures

Relic gravitons and high-frequency detectors [CL]

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http://arxiv.org/abs/2303.11928


Cosmic gravitons are expected in the MHz-GHz regions that are currently unreachable by the operating wide-band interferometers and where various classes of electromechanical detectors have been proposed through the years. The minimal chirp amplitude detectable by these instruments is often set on the basis of the sensitivities reachable by the detectors currently operating in the audio band. By combining the observations of the pulsar timing arrays, the limits from wide-band detectors and the other phenomenological bounds we show that this requirement is far too generous and even misleading since the actual detection of relic gravitons well above the kHz would demand chirp and spectral amplitudes that are ten or even fifteen orders of magnitude smaller than the ones currently achievable in the audio band, for the same classes of stochastic sources. We then examine more closely the potential high-frequency signals and show that the sensitivity in the chirp and spectral amplitudes must be even smaller than the ones suggested by the direct and indirect constraints on the cosmic gravitons. We finally analyze the high-frequency detectors in the framework of Hanbury-Brown Twiss interferometry and argue that they are actually more essential than the ones operating in the audio band (i.e. between few Hz and few kHz) if we want to investigate the quantumness of the relic gravitons and their associated second-order correlation effects. We suggest, in particular, how the statistical properties of thermal and non-thermal gravitons can be distinguished by studying the corresponding second-order interference effects.

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M. Giovannini
Wed, 22 Mar 23
22/68

Comments: 42 pages, 13 figures

Axion-sourced fireballs from supernovae [CL]

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http://arxiv.org/abs/2303.11395


New feebly interacting particles would emerge from a supernova core with 100-MeV-range energies and produce $\gamma$-rays by subsequent decays. These would contribute to the diffuse cosmic $\gamma$-ray background or would have shown up in the Solar Maximum Mission (SMM) satellite from SN~1987A. However, we show for the example of axion-like particles (ALPs) that, even at distances beyond the progenitor star, the decay photons may not escape, and can instead form a fireball, a plasma shell with $T\lesssim 1$ MeV. Thus, existing arguments do not exclude ALPs with few 10 MeV masses and a two-photon coupling of a few $10^{-10}~{\rm GeV}^{-1}$. However, the energy would have showed up in sub-MeV photons, which were not seen from SN 1987A in the Pioneer Venus Orbiter (PVO), closing again this new window. A careful re-assessment is required for other particles that were constrained in similar ways.

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M. Diamond, D. Fiorillo, G. Marques-Tavares, et. al.
Wed, 22 Mar 23
24/68

Comments: 11 pages, 6 figures

Searching for Time-Dependent Axion Dark Matter Signals in Pulsars [CEA]

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http://arxiv.org/abs/2303.11792


Axion dark matter can be converted into photons in the magnetospheres of neutron stars leading to a spectral line centred on the Compton wavelength of the axion. Due to the rotation of the star and the plasma effects in the magnetosphere the signal is predicted to be periodic with significant time variation – a unique smoking gun for axion dark matter. As a proof of principle and to develop the methodology, we carry out the first time domain search of the signal using data from PSR J2144$-$3933 taken as part of the MeerTIME project on MeerKAT telescope. We search for specific signal templates using a matched filter technique and discuss when a time-domain analysis (as is typically the case in pulsar observations) gives greater sensitivity to the axion-coupling to photons in comparison to a simple time-averaged total flux study. We do not find any candidate signals and, hence, impose an upper limit on the axion-to-photon coupling of $g_{a\gamma\gamma}<4\times 10^{-11}\,{\rm GeV}^{-1}$ over the mass range $m_{\rm a}=3.9-4.7\,\mu{\rm eV}$ using this data. This limit relies on PSR J2144$-$3933 not being an extremely aligned rotator, as strongly supported by simple arguments based on the observed pulse profile width. We discuss the possibilities of improving this limit using future observations with MeerKAT and also SKA1-mid and the possibility of using other objects. Finally, to evade modelling uncertainties in axion radio signals, we also carry out a generic “any periodic-signal search” in the data, finding no evidence for an axion signal.

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R. Battye, M. Keith, J. McDonald, et. al.
Wed, 22 Mar 23
26/68

Comments: 21 pages, 14 figures Comments welcome

Barrow nearly-extensive Gibbs-like entropy favoured by the full dynamical and geometrical data set in cosmology [CEA]

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http://arxiv.org/abs/2303.11680


We apply the full set of most update dynamical and geometrical data in cosmology to the nonextensive Barrow entropic holographic dark energy. We show that the data point towards an extensive Gibbs-like entropic behaviour for the cosmological horizons, which is the extreme case of the Barrow entropy, with the entropy parameter being $\Delta > 0.86$, close to the maximum threshold of $\Delta =1$ where the fractal dimension of the area-horizon becomes almost or just the volume and the intensivity is recovered. Futhermore, we find that the standard Bekenstein area-entropy limit ($\Delta = 0$) is excluded by the set of our data. This contradicts the bounds obtained recently from early universe tests such as the baryon asymmetry, the big-bang nucleosynthesis, and the inflation limiting $\Delta< 0.008$ at the most extreme case.

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T. Denkiewicz, V. Salzano and M. Dabrowski
Wed, 22 Mar 23
37/68

Comments: 11 pages; 2 tables. Comments are welcome

Strongly interacting matter exhibits deconfined behavior in massive neutron stars [HEAP]

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http://arxiv.org/abs/2303.11356


The inner cores of massive neutron stars contain strongly interacting matter at the highest densities reached in our Universe. Under these conditions the cores may undergo a phase transition to deconfined quark matter, which exhibits approximate conformal symmetry. Using a Bayesian inference setup that utilizes all available neutron-star measurements and state-of-the-art theoretical calculations, we demonstrate that in the cores of the most massive stars the equation of state is consistent with the presence of deconfined quark matter. We do this by (i) establishing an effective conformal symmetry restoration with 88% credence at the highest densities probed in these objects, and (ii) demonstrating that the number of active degrees of freedom favors an interpretation of this finding in terms of the presence of deconfined matter. The remaining probability for purely hadronic maximal-mass stars arises from equation-of-state behavior featuring small sound-speed and polytropic-index values, consistent with a first-order phase transition.

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E. Annala, T. Gorda, J. Hirvonen, et. al.
Wed, 22 Mar 23
39/68

Comments: 12 pages, 7 figures

Dark Matter Minihalos from Primordial Magnetic Fields [CEA]

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http://arxiv.org/abs/2303.11861


Primordial magnetic fields (PMF) can enhance baryon perturbations on scales below the photon mean free path. However, a magnetically driven baryon fluid becomes turbulent near recombination, thereby damping out baryon perturbations below the turbulence scale. In this letter, we show that the growth of baryon perturbations is imprinted in the dark matter perturbations, which are unaffected by turbulence and eventually collapse to form $10^{-11}-10^3\ M_{\odot}$ dark matter minihalos. In the process, we analytically derive the evolution of the PMF power spectrum in the viscous drag regime. If the magnetic fields purportedly detected in the blazar observations are PMFs generated after inflation and have a Batchelor spectrum, then such PMFs should also produce minihalos.

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P. Ralegankar
Wed, 22 Mar 23
53/68

Comments: 5 pages + 6 pages appendices

Hunting for Neutral Leptons with Ultra-High-Energy Cosmic Rays [CL]

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http://arxiv.org/abs/2303.11352


Next-generation large-volume detectors, such as GRAND, POEMMA, Trinity, TAROGE-M, and PUEO, have been designed to search for ultra-high-energy cosmic rays (UHECRs) with unprecedented sensitivity. We propose to use these detectors to search for new physics beyond the Standard Model (BSM). By considering the simple case of a right-handed neutrino that mixes exclusively with the active $\tau$ neutrino, we demonstrate that the existence of new physics can increase the probability for UHECRs to propagate through the Earth and produce extensive air showers that will be measurable soon. We compare the fluxes of such showers that would arise from various diffuse and transient sources of high-energy neutrinos, both in the Standard Model and in the presence of a right-handed neutrino. We show that detecting events with emergence angles $\gtrsim 10$ deg is promising to probe the existence of BSM physics, and we study the sensitivity of GRAND and POEMMA to do so. In particular, we show that the hypothesis of a right-handed neutrino with a mass of $\mathcal O(1-16)$ GeV may be probed in the future for mixing angles as small as $|U_{\tau N}|^2 \gtrsim 10^{-7}$, thus competing with existing and projected experimental limits.

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R. Heighton, L. Heurtier and M. Spannowsky
Wed, 22 Mar 23
56/68

Comments: 14 pages, 11 figures

Absorption of Vector Dark Matter Beyond Kinetic Mixing [CL]

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http://arxiv.org/abs/2303.11344


Massive vector particles are minimal dark matter candidates that motivate a wide range of laboratory searches, primarily exploiting a postulated kinetic mixing with the photon. However, depending on the high energy field content, the dominant vector dark matter (VDM) coupling to visible particles may arise at higher operator dimension, motivating efforts to predict direct detection rates for more general interactions. Here we present the first calculation of VDM absorption through its coupling to electron electric (EDM) or magnetic (MDM) dipole moments, which can be realized in minimal extensions to the Standard Model and yield the observed abundance through a variety of mechanisms across the eV\,-\,MeV mass range. We compute the absorption rate of the MDM and EDM models for a general target, and then derive direct detection constraints from targets currently in use: Si and Ge crystals and Xe and Ar atoms. We find that current experiments are already sensitive to VDM parameter space corresponding to a cosmological freeze-in scenario, and future experiments will be able to completely exclude MDM and EDM freeze-in models with reheat temperatures below the electroweak scale. Additionally, we find that while constraints on the MDM interaction can be related to constraints on axion-like particles, the same is not true for the EDM model, so the latter absorption rate must be computed from first principles. To achieve this, we update the publicly available program EXCEED-DM to perform these new calculations.

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G. Krnjaic and T. Trickle
Wed, 22 Mar 23
60/68

Comments: 23 pages, 3 figures

Exploring TeV candidates of Fermi blazars through machine learning [HEAP]

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http://arxiv.org/abs/2303.10557


In this work, we make use of a supervised machine learning algorithm based on Logistic Regression (LR) to select TeV blazar candidates from the 4FGL-DR2 / 4LAC-DR2, 3FHL, 3HSP, and 2BIGB catalogs. LR constructs a hyperplane based on a selection of optimal parameters, named features, and hyper-parameters whose values control the learning process and determine the values of features that a learning algorithm ends up learning, to discriminate TeV blazars from non-TeV blazars. In addition, it gives the probability (or logistic) that a source may be considered as a TeV blazar candidate. Non-TeV blazars with logistics greater than 80% are considered high-confidence TeV candidates. Using this technique, we identify 40 high-confidence TeV candidates from the 4FGL-DR2 / 4LAC-DR2 blazars and we build the feature hyper-plane to distinguish TeV and non-TeV blazars. We also calculate the hyper-planes for the 3FHL, 3HSP, and 2BIGB. Finally, we construct the broadband spectral energy distributions (SED) for the 40 candidates, testing for their detectability with various instruments. We find that 7 of them are likely to be detected by existing or upcoming IACT observatories, while 1 could be observed with EAS particle detector arrays.

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J. Zhu, C. Lin, H. Xiao, et. al.
Tue, 21 Mar 23
8/68

Comments: N/A

Revisiting Puffy Dark Matter with Novel Insights: Partial Wave Analysis [CL]

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http://arxiv.org/abs/2303.11058


We present a comprehensive study on the self-interaction cross-section of puffy dark matter (DM) particles, which have a significant intrinsic size compared to their Compton wavelength. For such puffy DM self-interaction cross-section in the resonant and classical regimes, our study demonstrates the significance of the Yukawa potential and the necessity of partial wave analysis: (i) Due to the finite-size effect of puffy DM particles, the new Yukawa potential of puffy DM is found to enlarge the Born-effective regime for the self-interaction cross-section, compared with the point-like DM; (ii) Our partial wave analysis shows that depending on the value of the ratio between $R_{\chi}$ (radius of a puffy DM particle) and $1/m_{\phi}$ (force range), the three regimes (Born-effective, resonant and classical) for puffy DM self-interaction cross-section can be very different from the point-like DM; (iii) We find that to solve the small-scale anomalies via self-interacting puffy DM, the Born-effective and the resonant regimes exist for dwarf galaxies, while for the cluster and Milky Way galaxy the non-Born regime is necessary.

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W. Wang, W. Xu, J. Yang, et. al.
Tue, 21 Mar 23
35/68

Comments: 17page, 8figure

Statistical anisotropy in galaxy ellipticity correlations [CEA]

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http://arxiv.org/abs/2303.10890


As well as the galaxy number density and peculiar velocity, the galaxy intrinsic alignment can be used to test the cosmic isotropy. We study distinctive impacts of the isotropy breaking on the configuration-space two-point correlation functions (2PCFs) composed of the spin-2 galaxy ellipticity field. For this purpose, we build a methodology to efficiently compute general types of the isotropy-violating 2PCFs by generalizing the polypolar spherical harmonic decomposition approach to the spin-weighted version. As a demonstration, we analyze the 2PCFs when the matter power spectrum has a well-known $g_*$-type isotropy-breaking term (induced by, e.g., dark vector fields). We then confirm that some anisotropic distortions indeed appear in the 2PCFs and their shapes rely on a preferred direction causing the isotropy violation, $\hat{d}$. Such a feature can be a distinctive indicator for testing the cosmic isotropy. Comparing the isotropy-violating 2PCFs computed with and without the plane parallel (PP) approximation, we find that, depending on $\hat{d}$, the PP approximation is no longer valid when an opening angle between the directions towards target galaxies is ${\cal O}(1^\circ)$ for the density-ellipticity and velocity-ellipticity cross correlations and around $10^\circ$ for the ellipticity auto correlation. This suggests that an accurate test for the cosmic isotropy requires the formulation of the 2PCF without relying on the PP approximation.

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M. Shiraishi, T. Okumura and K. Akitsu
Tue, 21 Mar 23
37/68

Comments: 21+1 pages, 8 figures

Primordial Gravitational Waves in non-Minimally Coupled Chromo-Natural Inflation [CEA]

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http://arxiv.org/abs/2303.10718


We consider inflation driven by an axion-like particle coupled to an SU(2) gauge sector via a Chern-Simons term. Known as chromo-natural inflation, this scenario is in tension with CMB observations. In order to remedy this fact and preserve both the symmetries and the intriguing gravitational wave phenomenology exhibited by the model, we explore the non-minimal coupling of the axion-inflaton to the Einstein tensor. We identify regions of parameter space corresponding to a viable cosmology at CMB scales. We also highlight the possibility of a large and chiral gravitational wave signal at small scales. This is of particular interest for gravitational wave interferometers.

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E. Dimastrogiovanni, M. Fasiello, M. Michelotti, et. al.
Tue, 21 Mar 23
64/68

Comments: 27 pages, 13 figures

Astrophysical and Cosmological Searches for Lorentz Invariance Violation [CEA]

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http://arxiv.org/abs/2303.10643


Lorentz invariance is one of the fundamental tenets of Special Relativity, and has been extensively tested with laboratory and astrophysical observations. However, many quantum gravity models and theories beyond the Standard Model of Particle Physics predict a violation of Lorentz invariance at energies close to Planck scale. This article reviews observational and experimental tests of Lorentz invariance violation (LIV) with photons, neutrinos and gravitational waves. Most astrophysical tests of LIV using photons are based on searching for a correlation of the spectral lag data with redshift and energy. These have been primarily carried out using compact objects such as pulsars, Active Galactic Nuclei (AGN), and Gamma-ray bursts (GRB). There have also been some claims for LIV from some of these spectral lag observations with GRBs, which however are in conflict with the most stringent limits obtained from other LIV searches. Searches have also been carried out using polarization measurements from GRBs and AGNs. For neutrinos, tests have been made using both astrophysical observations at MeV energies (from SN 1987A) as well as in the TeV-PeV energy range based on IceCube observations, atmospheric neutrinos, and long-baseline neutrino oscillation experiments. Cosmological tests of LIV entail looking for a constancy of the speed of light as a function of redshift using multiple observational probes, as well as looking for birefringence in Cosmic Microwave background observations. This article will review all of these aforementioned observational tests of LIV, including results which are in conflict with each other.

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S. Desai
Tue, 21 Mar 23
67/68

Comments: 31 pages. Comments welcome. Invited chapter for the edited book {\it Recent Progress on Gravity Tests: Challenges and Future Perspectives} (Eds. C. Bambi and A. C\’ardenas-Avenda\~no, Springer Singapore, expected in 2023)

Model-independent bubble wall velocities in local thermal equilibrium [CEA]

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http://arxiv.org/abs/2303.10171


Accurately determining bubble wall velocities in first-order phase transitions is of great importance for the prediction of gravitational wave signals and the matter-antimatter asymmetry. However, it is a challenging task which typically depends on the underlying particle physics model. Recently, it has been shown that assuming local thermal equilibrium can provide a good approximation when calculating the bubble wall velocity. In this paper, we provide a model-independent determination of bubble wall velocities in local thermal equilibrium. Our results show that, under the reasonable assumption that the sound speeds in the plasma are approximately uniform, the hydrodynamics can be fully characterized by four quantities: the phase strength $\alpha_n$, the ratio of the enthalpies in the broken and symmetric phases, $\Psi_n$, and the sound speeds in both phases, $c_s$ and $c_b$. We provide a code snippet that allows for a determination of the wall velocity and energy fraction in local thermal equilibrium in any model. In addition, we present a fit function for the wall velocity in the case $c_s = c_b = 1/\sqrt 3$.

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W. Ai, B. Laurent and J. Vis
Mon, 20 Mar 23
12/51

Comments: 32 pages, 5 figures