arXiv subjects

Maxim Yu. Khlopov

Publications and source records attributed to Maxim Yu. Khlopov.

At least 37 records · Page 2Linked to original sources

arXiv2020

Multi-messenger cosmology of new physics

The observational evidence for the inflationary cosmology with baryosynthesis and dark matter/energy can be viewed as the messenger for new physics, which governed the Universe origin, evolution and structure. To specify the physics beyond the Standard model (BSM), underlying the modern cosmological paradigm additional model dependent messengers are proposed, involving multi-component and composite dark matter, meta-stable particles, primordial black holes and antimatter domains in baryon asymmetrical Universe.

hep-ph↗

arXiv2020

Gravitino and Polonyi production in supergravity

We study production of gravitino and Polonyi particles in the minimal Starobinsky-Polonyi $\mathcal{N}=1$ supergravity with inflaton belonging to a massive vector supermultiplet. Our model has only one free parameter given by the scale of spontaneous SUSY breaking triggered by Polonyi chiral superfield. The vector supermultiplet generically enters the action non-minimally, via an arbitrary real function. This functon is chosen to generate the inflaton scalar potential of the Starobinsky model. Our supergravity model can be reformulated as an abelian supersymmetric gauge theory with the vector gauge superfield coupled to two (Higgs and Polonyi) chiral superfields interacting with supergravity, where the $U(1)$ gauge symmetry is spontaneously broken. We find that Polonyi and gravitino particles are efficiently produced during inflation. After inflation, perturbative decay of inflaton also produces Polonyi particles that rapidly decay into gravitinos. As a result, a coherent picture of inflation and dark matter emerges, where the abundance of produced gravitinos after inflation fits the CMB constraints as a Super Heavy Dark Matter (SHDM) candidate. Our scenario avoids the notorous gravitino and Polonyi problems with the Big Bang Nucleosynthesis (BBN) and DM overproduction.

hep-ph↗

arXiv2020

Influence of Modification of Gravity on the Complexity Factor of Static Spherical Structures

The aim of this paper is to generalize the definition of complexity for the static self-gravitating structure in $f(R,T,Q)$ gravitational theory, where $R$ is the Ricci scalar, $T$ is the trace part of energy momentum tensor and $Q\equiv R_{αβ}T^{αβ}$. In this context, we have considered locally anisotropic spherical matter distribution and calculated field equations and conservation laws. After the orthogonal splitting of the Riemann curvature tensor, we found the corresponding complexity factor with the help of structure scalars. It is seen that the system may have zero complexity factor if the effects of energy density inhomogeneity and pressure anisotropy cancel the effects of each other. All of our results reduce to general relativity on assuming $f(R,T,Q)=R$ condition.

gr-qc↗

arXiv2019

Conspiracy of BSM physics and cosmology

The lack of experimental evidence at the LHC for physics beyond the Standard model (BSM) of elementary particles together with necessity of its existence to provide solutions of internal problems of the Standard model (SM) as well as of physical nature of the basic elements of the modern cosmology demonstrates the conspiracy of BSM physics. Simultaneously the data of precision cosmology only tighten the constraints on the deviations from the now standard LambdaCDM model and thus exhibit conspiracy of the nonstandard cosmological scenarios. We show that studying new physics in combination of its physical, astrophysical and cosmological probes, can not only unveil the conspiracy of BSM physics but will also inevitably reveal nonstandard features in the cosmological scenario.

hep-ph↗

arXiv2019

Late time evolution of a nonminimally coupled scalar field system

We revisit the dynamics of a nonminimally coupled scalar field model in case of $F(ϕ)R$ coupling with $F(ϕ)= 1-ξϕ^2 $, and the potentials $V(ϕ) = V_0 (1+ ϕ^p)^2$, $V(ϕ)= V_0 e^{λϕ^2}$. We use an autonomous system to bring out new asymptotic regimes, and find stable de-Sitter solution. Under the chosen functional form of $F(ϕ)$ and steep exponential potentials, a true de-Sitter solution is trivially satisfied for which the equation of state $w_ϕ\simeq -1$, the effective gravitational constant $G_{eff}$ and field $ϕ$ are constant that has been missed in the power law case and our previous study.

gr-qc↗

arXiv2019

Hadronic and hadron-like physics of Dark Matter

The problems of simple elementary weakly interacting massive particles (WIMPs) appeal to extend the physical basis for nonbaryonic dark matter. Such extension involves more sophisticated dark matter candidates from physics beyond the Standard Model (BSM) of elementary particles. We discuss several models of dark matter, predicting new colored, hyper-colored or techni-colored particles and their accelerator and non-accelerator probes. The nontrivial properties of the proposed dark matter candidates can shed new light on the dark matter physics. They provide interesting solutions for the puzzles of direct and indirect dark matter search.

hep-ph↗

arXiv2019

Clusters of primordial black holes

The Primordial Black Holes (PBHs) are gradually involved into consideration as the phenomenon having reliable basis. We discuss here the possibility of their agglomeration into clusters that may have several prominent observable features. The clusters can form due to closed domain walls appearance in the natural and the hybrid inflation with subsequent evolution and gravitational collapse. Early dustlike stages of dominance of heavy metastable dissipative particles, at which star-like objects are formed, can also naturally lead to formation of black hole clusters, remaining in the Universe after decay of particles, from which they have originated. The dynamical evolution of such clusters discussed here is of the crucial importance. Such a model inherits all the advantages of the single PBHs like possible explanation of existence of supermassive black holes (origin of the early quasars), binary BH merges registered by LIGO/Virgo through gravitational waves, contribution to reionization of the Universe, but also has additional benefits. The cluster could alleviate or completely avoid existing constraints on the single PBH abundance making PBHs a real dark matter candidate. The most of existing constraints on (single) PBH density should be re-considered as applied to the clusters. Also unidentified cosmic gamma-ray point-like sources could be (partially) accounted for by them. One can conclude, that it seems really to be much more viable model with respect to the single PBHs.

astro-ph.CO↗

arXiv2019

Superheavy objects composed of nuclear and dark matter

We consider a model of $O$He atomic dark matter formed by Coulomb binding of the hypothetical stable double-charged massive $O^{--}$ particles with nuclei of primordial helium. Such a dark matter can be captured by ordinary matter forming superheavy nuclei. We propose a possibility of self-bound by nuclear and electromagnetic interaction $O$-nuclearites as well as more massive gravitating ones and discuss effect of accumulation of $O$He atoms in stars and their effect in stellar evolution.

hep-ph↗

arXiv2019

Double charged heavy constituents of dark atoms and superheavy nuclear objects

We consider the model of composite dark matter assuming stable particles of charge $-2$ bound with primordial helium nuclei by Coulomb force in $O$He atoms. We study capture of such dark atoms in matter and propose a possibility of existence of stable $O$-enriched superheavy nuclei and $O$-nuclearites, in which heavy $O$-dark matter fermions are bound by electromagnetic forces with ordinary nuclear matter. $O$He atoms accumulation in stars and its possible effect in stellar evolution is also considered, extending the set of indirect probes for composite dark matter.

hep-ph↗

arXiv2018

Beyond the Standard models of particle physics and cosmology

The modern Standard cosmological model of inflationary Unvierse and baryosynthesis deeply involves particle theory beyond the Standard model (BSM). Inevitably, models of BSM physics lead to cosmological scenarios beyond the Standard cosmological paradigm. Scenarios of dark atom cosmology in the context of puzzles of direct and indirect dark matter searches, of clusters of massive primordial black holes as the source of gravitational wave signals and of antimatter globular cluster as the source of cosmic antihelium are discussed.

astro-ph.CO↗

arXiv2018

Solar neutrino flare, megaton neutrino detectors and human space journey

The largest solar flare have been recorded in gamma flash and hard spectra up to tens GeV energy. The present building and upgrade of Hyper- Kamiokande (HK) in Japan and Korea, (as well as Deep Core, PINGU) Megatons neutrino detectors do offer a novel way to detectable trace of solar flares: their sudden anti-neutrino (or neutrino) imprint made by proton scattering and pion decays via Delta resonance production on solar corona foot-point. These signals might be observable at largest flare by HK via soft spectra up to tens-hundred MeV energy and by IceCube-PINGU at higher, GeVs energies. We show the expected rate of signals for the most powerful solar flare occurred in recent decades extrapolated for future Megaton detectors. The neutrino solar flare detection with its prompt alarm system may alert astronauts on space journey allowing them to hide themselves into inner rocket container surrounded by fuel or water supply. These container walls are able to defend astronauts from the main lethal (the dominant soft component) radiation wind due to such largest solar flares.

astro-ph.HE↗

arXiv2018

Where are the Ultra High Energy Cosmic Ray (UHECR) originated?

We consider the recent results on UHECR (Ultra High Energy Cosmic Ray) composition and their distribution in the sky from ten EeV energy (the dipole anisotropy) up to the highest UHECR energies and their clustering maps: UHECR have been found mostly made by light and lightest nuclei. We summarized the arguments that favor a few localized nearby extragalactic sources for most UHECR as CenA, NG 253, M82. We comment also on the possible partial role of a few remarkable galactic UHECR sources. Finally we revive the eventual role of a relic neutrino eV mass in dark hot halo (hit by ZeV neutrinos) to explain the new UHECR clustering events centered around a very far cosmic AGN sources as 3C 454.

astro-ph.HE↗

arXiv2018

May GWs signals by BH BH merging be associated with any gamma or neutrino burst? The case of a NS NS merging in GW GRB170817A

The Gravitational Wave (GW) events GW150914, GW151226, GW170104 detected by LIGO were a record of Black Hole binary merging system (BH-BH) very probably in nearly empty or a vacuum space; such a kind of events will be mostly with no baryon mass (plasma or dense masses) and therefore mute or blind in any correlated gamma band. If the GWs events might be born inside a globular cluster, a star forming region or along a spiral AGN accretion disk their additional accreting mass may be the needed baryon load to explode and shine: in those dense places. BH BH collapse may also offer an optical X and gamma afterglow via their baryon lightening and photon tracks. Only very nearby (tens Mpc) BH Neutron Star (NS) or NS NS cannibal merging might be guaranteed and associated also with a desired, visible and correlated spherical NS explosion (kilonova one); they require much lower threshold or just nearer distances. Indeed such a very exceptional GW170817 GRB170817a event occurred last August 2017; it took place and it was related to a very first NS NS collapse in a SN kilonova spherical explosion. The GRB170817a gamma, X, radio signature it was exceptional in many features . Its unique values (softer, weaker, the most near and long life one) made GRB170817a very possibly an off-axis jet detection. However there are solid arguments that suggest that such a GRB are not just blazing within a collimated beam jet but that they are also shining in a wider spread gamma equatorial disk blazing, orthogonal to the jet itself. In a few words we were observing the event not along its jet but mostly orthogonal to it. This GRB170817a geometry may better explain the otherwise unexpected beamed to us event. In this paper therefore we summarize the astrophysical and the cosmological signature of such a long desired multiple astronomy.

astro-ph.HE↗

arXiv2018

Probes for Dark Matter Physics

The existence of cosmological dark matter is in the bedrock of the modern cosmology. The dark matter is assumed to be nonbaryonic and to consist of new stable particles. However if composite dark matter contains stable electrically charged leptons and quarks bound by ordinary Coulomb interaction in elusive dark atoms, these charged constituents of dark atoms can be the subject of direct experimental test at the colliders. In such models the excessive negatively double charged particles are bound with primordial helium in O-helium atoms, maintaining specific nuclear-interacting form of the dark matter. The successful development of composite dark matter scenarios appeals to experimental search for doubly charged constituents of dark atoms, making experimental search for exotic stable double charged particles experimentum crucis for dark atoms of composite dark matter. (abridged)

hep-ph↗

arXiv2017

Signals of HE atmospheric muon decay in flight around the Sun's albedo versus astrophysical muon and tau neutrino traces in the Moon's shadow

The Sun albedo of cosmic rays at GeVs energy has been discovered recently by FERMI satellite. They are traces of atmospheric CR hitting solar atmosphere and reflecting skimming gamma photons. Even if relevant for astrophysics, as being trace of atmospheric solar Cosmic Ray noises they cannot offer any signal of neutrino astronomy. On the contrary the Moon, with no atmosphere, may become soon a novel filtering calorimeter and an amplifier of energetic muon astronomical neutrinos (at TeV up to hundred TeV energy); these lepton tracks leave an imprint in their beta decay while in flight to Earth. Their TeV electron air-shower are among the main signals. Also a more energetic, but more rare, PeV up to EeV tau lunar neutrino events may be escaping as a tau lepton from the Moon: PeVs secondaries may be shining on Earth atmosphere in lunar shadows in a surprising rich way. One or a few gamma air-shower event inside the Moon shadows may occur each year in near future CTA or LHAASO TeVs gamma array detector, assuming a non negligible astrophysical TeV up to hundred TeV neutrino component (respect to our terrestrial ruling atmospheric ones); these signals will open a new wonderful passepartout keyhole for neutrino been seen along the Moon. The lunar solid angle is small and the muon or tau expected rate is rare, but future largest tau radio array as GRAND one might well discover such neutrino imprint.

astro-ph.HE↗

arXiv2017

Testing B-violating signatures from Exotic Instantons in future colliders

We discuss possible implications of Exotic Stringy instantons for Baryon-violating signatures in future colliders. In particular, we discuss high-energy quarks collisions and $Λ-\barΛ$ transitions. In principle, $Λ-\barΛ$ process can be probed by high-luminosity electron-positron colliders. However, we find that an extremely high luminosity is needed in order to provide a (somewhat) stringent bound compared to the current data on $NN\rightarrow ππ,KK$. On the other hand, (exotic) instanton-induced six quark interactions can be tested in near future high-energy colliders beyond LHC, at energies around $20-100\, \rm TeV$. Super proton-proton collider (SppC) is capable of such measurement given the proposed energy level of 50-90 TeV. Comparison with other channels is made. In particular, we show the compatibility of our model with neutron-antineutron and $NN\rightarrow ππ,KK$ bounds.

hep-ph↗

arXiv2017

Dark Matter from Starobinsky Supergravity

We review our recent results on dark matter from Starobinsky supergravity. In this context, a natural candidate for Cold Dark Matter is the gravitino. On the other hand, assuming the supersymmetry broken at scales much higher than the electroweak scale, gravitinos are super heavy particles. In this case, they may be non-thermally produced during inflation, in turn originated by the scalaron field with Starobinsky's potential.Assuming gravitinos as Lightest supersymmetric particles (LSSP), the non-thermal production naturally accounts for the right amount of cold dark matter. Metastability of the gravitino LSSP leads to observable effects of their decay, putting constraints on the corresponding Unstable or Decaying Dark Matters scenarios. In this model, the gravitino mass is controlled by the inflaton field and it runs with it. This implies that a continuous spectrum of superheavy gravitinos is produced during the slow-roll epoch. Implications in phenomenology, model building in GUT scenarios, intersecting D-branes models and instantons in string theories are discussed.

gr-qc↗

arXiv2016

Dark Matter and Inflation in $R+ζR^{2}$ Supergravity

As is well known, the gravitational degrees of freedom contained in $R+ζR^{2}$ (super)gravity lead to Starobinsky's potential, in a one-field setting for inflationary Cosmology that appears favored by Planck data. In this letter we discuss another interesting aspect of this model, related to gravitino production, with emphasis on the corresponding mass spectrum. Assuming that supersymmetry is broken at a very high scale, Super Heavy Gravitino Dark Matter (SHGDM) and Starobinsky's inflation can be coherently unified in a $R+ζR^{2}$ supergravity. Gravitinos are assumed to be the Lightest Supersymmetric Particles (LSP) and are non-thermally produced during inflation, in turn originated by a scalar with a Starobinsky's potential. Gravitino mass runs with the inflaton field, so that a continuos spectrum of superheavy gravitinos emerges. The theory is implemented with a $U(1)_{R}$ gauge symmetry. However, in a string UV completion, $U(1)_{R}$-symmetry can be broken by non-perturbative string instantons, while for consistency of our scenario $U(1)_{R}$ gauge symmetry breaking must be broken in order to generate a soft mass terms for the gravitino and gauginos. R-parity violating operators can be generated at non-perturbative level. Gravitinos can decay into very energetic neutrinos and photons in cosmological time scale, with intriguing implications for high energy cosmic rays experiments.

gr-qc↗