# Dark Matter, Neutrino mass, Cutoff for Cosmic-Ray Neutrino, and Higgs Boson Invisible Decay from a Neutrino Portal Interaction [CL]

We study an effective theory beyond the standard model (SM) where either of two additional gauge singlets, a Majorana fermion and a real scalar, constitute all or some fraction of dark matter. The only additional interaction to the SM is via a dimension-five lepton number preserving operator: a neutrino portal interaction. We point out that this interaction (i) generates the neutrino mass radiatively, (ii) gives a cutoff for the cosmic-ray neutrino, and (iii) induces the testable Higgs boson invisible decay in the future lepton colliders, such as the CEPC, ILC, and CLIC. In particular, there are two correlated phenomena. If the dark matter is detected in XENON1T, XENONnT, LZ, DARWIN, or PandaX in future, the Higgs invisible decay is within the reach of the future lepton colliders. If a high energy cutoff of cosmic-ray neutrino, which may account for the non-detection of GZK neutrinos or Glashow resonance, is generated due to its annihilation with the cosmic background neutrino, the Higgs invisible decay can be searched for in these colliders. Moreover, the scale for one of the neutrino masses is predicted. The UV completion and the fine tuning, as well as the constraints from collider physics, cosmology, and astronomy are discussed.

W. Yin
Thu, 22 Jun 17
12/68

# Braneworld wormholes supported by astrophysical observations [CL]

In this study, we investigate the characteristics and properties of a traversable wormhole constrained by the current astrophysical observations in the framework of modified theories of gravity (MOG). As a concrete case, we study traversable wormhole space–time configurations in the Dvali–Gabadadze–Porrati (DGP) braneworld scenario, which are supported by the effects of the gravity leakage of extra dimensions. We find that the wormhole space–time structure will open in terms of the $2\sigma$ confidence level when we utilize the joint constraints supernovae (SNe) Ia + observational Hubble parameter data (OHD) + Planck + gravitational wave (GW) and $z<0.2874$. Furthermore, we obtain several model-independent conclusions, such as (i) the exotic matter threading the wormholes can be divided into four classes during the evolutionary processes of the universe based on various energy conditions; (ii) we can offer a strict restriction to the local wormhole space–time structure by using the current astrophysical observations; and (iii) we can clearly identify a physical gravitational resource for the wormholes supported by astrophysical observations, namely the dark energy components of the universe or equivalent space–time curvature effects from MOG. Moreover, we find that the strong energy condition is always violated at low redshifts.

D. Wang and X. Meng
Thu, 22 Jun 17
15/68

Comments: 11 pages, 8 figures, accepted for publication in Frontiers of Physics

# Kerr black holes with synchronised hair: an analytic model and dynamical formation [CL]

East and Pretorius (arXiv:1704.04791) have successfully evolved, using fully non-linear numerical simulations, the superradiant instability of the Kerr black hole (BH) triggered by a massive, complex vector field. Evolutions terminate in stationary states of a vector field condensate synchronised with a rotating BH horizon. We show these end points are fundamental states of Kerr BHs with synchronised Proca hair. Motivated by the “experimental data” from these simulations we suggest a universal (i.e. field-spin independent), analytic model for the subset of BHs with sychronised hair that possess a quasi-Kerr horizon, applicable in the weak hair regime. Comparing this model with fully non-linear numerical solutions of BHs with synchronised scalar or Proca hair, we show the model is accurate for hairy BHs that may emerge dynamically from superradiance, whose domain we identify.

Thu, 22 Jun 17
34/68

Comments: 5+2 pages, 7 figures; data files and Mathematica notebooks can be found in this URL: this http URL

# Early propagation of energetic particles across the mean field in turbulent plasmas [CL]

Propagation of energetic particles across the mean field direction in turbulent magnetic fields is often described as spatial diffusion. Recently, it has been suggested that initially the particles propagate systematically along meandering field lines, and only later reach the time-asymptotic diffusive cross-field propagation. In this paper, we analyse cross-field propagation of 1–100 MeV protons in composite 2D-slab turbulence superposed on a constant background magnetic field, using full-orbit particle simulations, to study the non-diffusive phase of particle propagation with a wide range of turbulence parameters. We show that the early-time non-diffusive propagation of the particles is consistent with particle propagation along turbulently meandering field lines. This results in a wide cross-field extent of the particles already at the initial arrival of particles to a given distance along the mean field direction, unlike when using spatial diffusion particle transport models. The cross-field extent of the particle distribution remains constant for up to tens of hours in turbulence environment consistent with the inner heliosphere during solar energetic particle events. Subsequently, the particles escape from their initial meandering field lines, and the particle propagation across the mean field reaches time-asymptotic diffusion. Our analysis shows that in order to understand solar energetic particle event origins, particle transport modelling must include non-diffusive particle propagation along meandering field lines.

T. Laitinen, S. Dalla and D. Marriott
Thu, 22 Jun 17
53/68

Comments: 11 pages, 9 figures; Accepted for publication in MNRAS

# Strong-field gravitational-wave emission in Schwarzschild and Kerr geometries: some general considerations [CL]

We show how the concurrent implementation of the exact solutions of the Einstein equations, of the equations of motion of the test particles, and of the relativistic estimate of the emission of gravitational waves from test particles, can establish a priori constraints on the possible phenomena occurring in Nature. Two examples of test particles starting at infinite distance or from finite distance in a circular orbit around a Kerr black hole are considered: the first leads to a well defined gravitational wave burst the second to a smooth merging into the black hole. We notice a difference between our treatment and the one by Ori and Thorne (2000) which will affect the gravitational wave signal. This analysis is necessary for the study of the waveforms in merging binary systems.

J. Rodriguez, J. Rueda and R. Ruffini
Wed, 21 Jun 17
2/64

# Binary Black Hole in a Double Magnetic Monopole Field [CL]

Ambient magnetic fields are thought to play a critical role in black hole jet formation. Furthermore, dual electromagnetic signals could be produced during the inspiral and merger of binary black hole systems. However, due to the absence of theoretical models, the physical status of binary black hole arrays with dual jets has remained unresolved. In this paper, we derive the exact solution for the electromagnetic field occurring when a static, axisymmetric binary black hole system is placed in the field of two magnetic or electric monopoles. As a by-product of this derivation, we also find the exact solution of the binary black hole configuration in a magnetic or electric dipole field. The presence of conical singularities in the static black hole binaries represent the gravitational attraction between the black holes that also drag the external two monopole field. We show that these off-balance configurations generate no energy outflows.

M. Rodriguez
Wed, 21 Jun 17
6/64

We consider the phantom braneworld cosmology in the context of the maximum turn around radius, $R_{\rm TA,max}$, of spherical cosmic structures. The maximum turn around radius is the point where the attraction due to the central inhomogeneity gets balanced with the repulsion of the ambient dark energy, beyond which a structure cannot hold any mass, thereby giving the maximum upper bound on the size of a stable structure. In this work we first derive an analytical expression of $R_{\rm TA,max}$ for this model. Using this we constrain its parameter space, including a bulk cosmological constant and the Weyl fluid, from the mass versus actual observed size data for some nearby large scale structures. We show in particular that a) in the absence of any bulk cosmological constant the predicted maximum size is always greater than what is actually observed b) same conclusion holds upon inclusion of a negative bulk cosmological constant and c) if the bulk cosmological constant is positive, the predicted maximum size can go below than what is actually observed, leading to interesting constraints on the parameter space of the theory