arXiv subjects

K. Belotsky

Publications and source records attributed to K. Belotsky.

12 recordsLinked to original sources

arXiv2019

Electromagnetic probes of primordial black holes as dark matter

The LIGO discoveries have rekindled suggestions that primordial black holes (BHs) may constitute part to all of the dark matter (DM) in the Universe. Such suggestions came from 1) the observed merger rate of the BHs, 2) their unusual masses, 3) their low/zero spins, and 4) also from the independently uncovered cosmic infrared background (CIB) fluctuations signal of high amplitude and coherence with unresolved cosmic X-ray background (CXB). Here we summarize the prospects to resolve this important issue with electromagnetic observations using the instruments and tools expected in the 2020's. These prospects appear promising to make significant, and potentially critical, advances. We demonstrate that in the next decade, new space- and ground-borne electromagnetic instruments, combined with concurrent theoretical efforts, should shed critical light on the long-considered link between primordial BHs and DM. Specifically the new data and methodologies under this program will involve: I) Probing with high precision the spatial spectrum of source-subtracted CIB with Euclid and WFIRST, and its coherence with unresolved cosmic X-ray background using eROSITA and Athena, II) Advanced searches for microlensing of Galactic stars by the intervening Galactic Halo BHs with OGLE, Gaia, LSST and WFIRST, III) Supernovae (SNe) lensing in the upcoming surveys with WFIRST, LSST and also potentially with Euclid and JWST, IV) Advanced theoretical work to understand the details of PBH accretion and evolution and their influence on cosmic microwave background (CMB) anisotropies in light of the next generation CMB experiments, V) Better new samples and theoretical understanding involving stability and properties of ultra faint dwarf galaxies, pulsar timing, and cosmological quasar lensing.

astro-ph.CO↗

arXiv2015

High Energy Positrons and Gamma Radiation from Decaying Constituents of a two-component Dark Atom Model

We study a two component dark matter candidate inspired by the Minimal Walking Technicolor model. Dark matter consists of a dominant SIMP-like dark atom component made of bound states between primordial helium nuclei and a doubly charged technilepton, and a small WIMP-like component made of another dark atom bound state between a doubly charged technibaryon and a technilepton. This scenario is consistent with direct search experimental findings because the dominant SIMP component interacts too strongly to reach the depths of current detectors with sufficient energy to recoil and the WIMP-like component is too small to cause significant amount of events. In this context a metastable technibaryon that decays to $e^+e^+$, $μ^+ μ^+$ and $τ^+ τ^+$ can in principle explain the observed positron excess by AMS-02 and PAMELA, while being consistent with the photon flux observed by FERMI/LAT. We scan the parameters of the model and we find the best possible fit to the latest experimental data. We find that there is a small range of parameter space that this scenario can be realised under certain conditions regarding the cosmic ray propagation and the final state radiation. This range of parameters fall inside the region where the current run of LHC can probe, and therefore it will soon be possible to either verify or exclude conclusively this model of dark matter.

astro-ph.HE↗

arXiv2013

Gamma-ray effects of dark forces in dark matter clumps

Existence of new gauge U(1) symmetry possessed by dark matter (DM) particles implies the existence of a new Coulomb-like interaction, which leads to Sommerfeld-Gamow-Sakharov enhancement of dark matter annihilation at low relative velocities. We discuss a possibility to put constraints on the such dark forces of dark matter from the observational data on the gamma radiation in our Galaxy. Gamma-rays are supposed to originate from annihilation of DM particles in the small scale clumps, in which annihilation rate is supposed to be enhanced, besides higher density, due to smaller relative velocities $v$ of DM particles. For possible cross sections, mass of annihilating particles, masses of clumps and the contribution of annihilating particles in the total DM density we constrain the strength of new dark long range forces from comparison of predicted gamma ray signal with Fermi/LAT data on unidentified point-like gamma-ray sources (PGS) as well as on diffuse $γ$-radiation.

astro-ph.HE↗

arXiv2008

Stable quarks of the 4th family?

Existence of metastable quarks of new generation can be embedded into phenomenology of heterotic string together with new long range interaction, which only this new generation possesses. We discuss primordial quark production in the early Universe, their successive cosmological evolution and astrophysical effects, as well as possible production in present or future accelerators. In case of a charge symmetry of 4th generation quarks in Universe, they can be stored in neutral mesons, doubly positively charged baryons, while all the doubly negatively charged "baryons" are combined with He-4 into neutral nucleus-size atom-like states. The existence of all these anomalous stable particles may escape present experimental limits, being close to present and future experimental test. Due to the nuclear binding with He-4 primordial lightest baryons of the 4th generation with charge +1 can also escape the experimental upper limits on anomalous isotopes of hydrogen, being compatible with upper limits on anomalous lithium. While 4th quark hadrons are rare, their presence may be nearly detectable in cosmic rays, muon and neutrino fluxes and cosmic electromagnetic spectra. In case of charge asymmetry, a nontrivial solution for the problem of dark matter (DM) can be provided by excessive (meta)stable anti-up quarks of 4th generation, bound with He-4 in specific nuclear-interacting form of dark matter. Such candidate to DM is surprisingly close to Warm Dark Matter by its role in large scale structure formation. It catalyzes primordial heavy element production in Big Bang Nucleosynthesis and new types of nuclear transformations around us.

astro-ph↗

arXiv2008

Correlation between regions of star formation and gamma-ray sources

Statistically significant correlation between positions of unidentified gamma-ray sources (UGS) and the regions of star formation (RSF) is found. Fraction of UGS, coincided in position with RSF, makes up $47\pm 8$%. The coincided discrete gamma-ray sources possess, on average, harder energetic spectra and larger intensities with respect to the rest UGS. Annihilation of dark matter concentrating in RSF is supposed to account for a possible origin of gamma-radiation.

astro-ph↗

arXiv2006

$^3$He experimentum crucis for Dark Matter puzzles

The leading direct dark matter search experiments: CDMS, Edelweis and DAMA/NaI exhibit different results for different approaches to the problem. This contradiction can reflect a nontrivial and probably a multi-component nature of the cosmological dark matter. WIMPs can possess dominantly a Spin Dependent interaction with nucleons. They can be superheavy or represent atom-like systems of superheavy charged particles. The Dark matter can contain a component, which strongly interacts with the matter. We show that even a moderate size superfluid $^3$He detector provides a crucial test for these hypotheses and that its existing laboratory prototype is already of interest for the experimental dark matter search.

astro-ph↗

arXiv2006

Stable matter of 4th generation: hidden in the Universe and close to detection?

Stable neutrino and U quark of 4th generation are excluded neither by experimental data, nor by astrophysical constraints. Moreover, excess of stable $\bar U$ quarks in the Universe can lead to an exciting composite nuclear-interacting form of dark matter, which can even dominate in large scale structure formation.

astro-ph↗

arXiv2005

On the distribution of collisionless particles in local potential well

The distribution of collisionless particles with infinite motion in the presence of a local potential well is discussed. Such distribution is important for interpretation of results of dark matter searches. The relationship n/v=const, where n and v are respectively number density and velocity of particles, is derived for particles crossing a local potential well. The limits of application of this relationship are specified.

astro-ph↗

arXiv2004

May Heavy hadrons of the 4th generation be hidden in our Universe while close to detection?

Metastable quarks of 4th generation are predicted in the framework of heterotic string phenomenology. Their presence in heavy stable hadrons are usually strongly constrained; however their hidden compositions in Heavy doubly charged baryons here considered are found to be still allowable: we studied their primordial quark production in the early Universe, their freezing into cosmic Heavy hadrons, their later annihilation into cosmic ray as well as their relic presence in our Universe and among us on Earth. We discuss also their possible production in present or future accelerators. Indeed if the lightest quarks and antiquarks of the 4th generation are stored in doubly charged baryons and neutral mesons, their lifetime can exceed the age of the Universe; the existence of such an anomalous Helium-like (and neutral Pion-like) stable particles may escape present experimental limits, while being close to present and future experimental test. On the contrary primordial abundance of lightest hadrons of the 4th generation with charge +1 can not decrease below the experimental upper limits on anomalous hydrogen and therefore (if stable) it is excluded. While 4th quark hadrons are rare, their presence may play different and surprising role in cosmic rays, muon and neutrino fluxes and cosmic electromagnetic spectra. Most of these traces are tiny, but just nearly detectable.

hep-ph↗

arXiv2004

May Heavy neutrinos solve underground and cosmic ray puzzles?

Primordial Heavy neutrinos of 4th generation might explain different astrophysical puzzles: indeed the simplest 4th neutrino scenario may be still consistent with known 4th neutrino physics, cosmic ray anti-matter and gamma fluxes and signals in underground detectors for a very narrow neutrino mass windows (46-47 GeV). We have analyzed extended Heavy neutrino models related to the clumpiness of neutrino density, new interactions in Heavy neutrino annihilation, neutrino asymmetry, neutrino decay. We found that in these models the underground signals maybe better combined with the cosmic ray imprint leading to a wider windows for neutrino mass (46-75 GeV) coinciding with the whole range allowed from uncertainties of electro-weak parameters.

hep-ph↗

arXiv2004

Can an invisible Higgs boson be seen via diffraction at the LHC?

We study the possibility of observing an `invisible' Higgs boson in central exclusive diffractive production at the LHC. We evaluate the cross section using, as a simple example, the Standard Model with a heavy fourth generation, where the invisible decay mode $H \to ν_4 \barν_4$ dominates, with the heavy neutrino mass $M(ν_4) \simeq 50$ GeV. We discuss the possible requirements on trigger conditions and the background processes.

hep-ph↗

arXiv2002

Invisible Higgs Boson Decay into Massive Neutrinos of 4th Generation

Results from several recent experiments provide inderect evidences in the favor of existence of a 4th generation neutrino. Such a neutrino of mass about 50 GeV is compatible with current physical and astrophysical constraints and well motivated in the framework of superstring phenomenology. If sufficiently stable the existence of such a neutrino leads to the drastic change of Higgs boson physics: for a wide range of Higgs boson masses the dominant mode of Higgs boson decay is invisible and the branching ratios for the most promising modes of Higgs boson search are significantly reduced. The proper strategy of Higgs boson searches in such a framework is discussed. It is shown that in the same framework the absence of a signal in the search for invisible Higgs boson decay at LEP means either that the mass of Higgs is greater than 113.5 GeV or that the mass difference between the Higgs mass and doubled neutrino mass is small.

hep-ph↗