arXiv subjects

M. Yu. Khlopov

Publications and source records attributed to M. Yu. Khlopov.

At least 55 records · Page 3Linked to original sources

arXiv2007

Dark matter from stable charged particles?

Particle physics candidates for cosmological dark matter are usually considered as neutral and weakly interacting. However stable charged leptons and quarks can also exist and, hidden in elusive atoms, play the role of dark matter. The necessary condition for such scenario is absence of stable particles with charge -1 and effective mechanism for suppression of free positively charged heavy species. These conditions are realized in several recently developed scenarios. In scenario based on Walking Technicolor model excess of stable particles with charge -2 and the corresponding dark matter density is naturally related with the value and sign of cosmological baryon asymmetry. The excessive charged particles are bound with primordial helium in techni-O-helium "atoms", maintaining specific nuclear-interacting form of dark matter. Some properties of techni-O-helium Universe are discussed.

astro-ph↗

arXiv2007

Primordial Black Holes

Primordial black holes (PBHs) are a profound signature of primordial cosmological structures and provide a theoretical tool to study nontrivial physics of the early Universe. The mechanisms of PBH formation are discussed and observational constraints on the PBH spectrum, or effects of PBH evaporation, are shown to restrict a wide range of particle physics models, predicting an enhancement of the ultraviolet part of the spectrum of density perturbations, early dust-like stages, first order phase transitions and stages of superheavy metastable particle dominance in the early Universe. The mechanism of closed wall contraction can lead, in the inflationary Universe, to a new approach to galaxy formation, involving primordial clouds of massive BHs created around the intermediate mass or supermassive BH and playing the role of galactic seeds.

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arXiv2007

Proceedings to the 10th Workshop 'What Comes Beyond the Standard Models', Bled, July 17. - 27., 2007, Slovenia

Contents: 1. Finestructure Constants at the Planck Scale from Multiple Point Principle (D.L.Bennett, L.V. Laperashvili and H.B. Nielsen) 2. Random Dynamics in Starting Levels (D. Bennett, A. Kleppe in H.B. Nielsen), 3. Families of Quarks and Leptons and Their Mass Matrices from the Approach Unifying Spins and Charges: Prediction for the Fourth Family (G. Bregar, M. Breskvar, D. Lukman and N.S. Mankoc Borstnik) 4. Fermion-Fermion and Boson-Boson Amplitudes: Surprising Similarities (V.V. Dvoeglazov) 5. Antisymmetric Tensor Fields, 4-Vector Fields, Indefinite Metrics and Normalization (V.V. Dvoeglazov) 6. Quantum Gates and Quantum Algorithms with Clifford Algebra Technique (M. Gregoric and N.S. Mankoc Borstnik) 7. From the Starting Lagrange Density to the Effective Fields for Spinors in the Approach Unifying Spins and Charges (N.S. Mankoc Borstnik) 8. New Generations of Particles in the Universe (M.Yu. Khlopov) 9. A Subversive View of Modern 'Physics' (R. Mirman) 10. Mass Spectra are Inherent in Geometry: an Analysis Using the Only Conformal Group Allowing a Universe (R. Mirman) 11. Complex Action, Prearrangement for Future and Higgs Broadening (H.B. Nielsen and M. Ninomiya) 12. Discussion on Dark Matter Candidates from the Approach Unifying Spins and Charges (G. Bregar and N.S. Mankoc Borstnik) 13. Discussion Section Summary on Dark Matter Particle Properties (M.Yu. Khlopov and N.S. Mankoc Borstnik)

hep-ph↗

arXiv2006

Search for Two-Particle Muon Decay to Positron and Goldstone Massless Boson (FAMILON)

The experimental test of possible expansion for the Higgs sector is proposed. The lepton family violation will be studied. To reach this goal we are going to carry out the search for the scalar Goldstone boson in the neutrinoless muon decay mu+ to e+ and alpha. The asymmetry of the muon decay near the high energy edge of Michel spectrum is to be measured. To examine previous TRIUMF data the experiment FAMILON is prepared at the surface muon beam of JINR (Dubna) accelerator. The setup consist of the precision magnetic spectrometer and the device for muSR - analysis.

hep-ex↗

arXiv2006

Proceedings to the 9th Workshop 'What Comes Beyond the Standard Models', Bled, September 16. - 26., 2006, Slovenia

Contents: 1. Child Universes in the Laboratory (S. Ansoldi and E.I. Guendelman) 2. Relation between Finestructure Constants at the Planck Scale from Multiple Point Principle (D.L. Bennett, L.V. Laperashvili and H.B. Nielsen) 3. On the Origin of Families of Fermions and Their Mass Matrices -- Approximate Analyses of Properties of Four Families Within Approach Unifying Spins and Charges (M. Breskvar, D. Lukman and N.S. Mankoc Borstnik) 4. Cosmoparticle Physics: Cross-disciplinary Study of Physics Beyond the Standard Model (M.Yu. Khlopov) 5. Discussion Section on 4th Generation (M.Yu. Khlopov) 6. Involution Requirement on a Boundary Makes Massless Fermions Compactified on a Finite Flat Disk Mass Protected (N.S. Mankoc Borstnik and H.B. Nielsen) 7. How Can Group Theory be Generalized so Perhaps Providing Further Information About Our Universe? (R. Mirman) 8. FutureDependent Initial Conditions from Imaginary Part in Lagrangian (H.B. Nielsen and M. Ninomiya) 9. Coupling Self-tuning to Critical Lines From Highly Compact Extra Dimensions (K. Petrov)

hep-ph↗

arXiv2006

Composite Dark Matter and its Charged Constituents

Stable charged heavy leptons and quarks can exist and hide in elusive atoms, bound by Coulomb attraction and playing the role of dark matter. However, in the expanding Universe it is not possible to recombine all the charged particles into such atoms, and the positively charged particles, which escape this recombination, bind with electrons in atoms of anomalous isotopes with pregalactic abundance, exceeding substantially the terrestrial upper limits. This abundance can not be reduced in the dense matter bodies, if negatively charged particles have charge -1. Therefore composite dark matter can involve only negatively charged particles with charge -2, while stable heavy particles with charge -1 should be excluded. Realistic scenarios of composite dark matter, avoiding this problem of anomalous isotope over-production, inevitably predict the existence of primordial "atoms", in which primordial helium traps all the free negatively charged heavy constituents with charge -2. Study of the possibility for such primordial heavy $α$ particle with compensated charge to exist as well as the search for the stable charged constituents in cosmic rays and accelerators provide crucial test for composite dark matter scenarios.

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arXiv2005

Effects of new long-range interaction: Recombination of relic Heavy neutrinos and antineutrinos

If stable Heavy neutrinos of 4th generation possess their own Coulomb-like interaction, recombination of pairs of Heavy neutrinos and antineutrinos can play important role in their cosmological evolution and lead to observable consequences. In particular, effect of this new interaction in the annihilation of neutrino-antineutrino pairs can account for $γ$-flux observed by EGRET.

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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↗

arXiv2003

Primordial pairing and binding of superheavy charge particles in the early Universe

Primordial superheavy particles, considered as the source of Ultra High Energy Cosmic Rays (UHECR) and produced in local processes in the early Universe, should bear some strictly or approximately conserved charge to be sufficiently stable to survive to the present time. Charge conservation makes them to be produced in pairs, and the estimated separation of particle and antiparticle in such pair is shown to be in some cases much smaller than the average separation determined by the averaged number density of considered particles. If the new U(1) charge is the source of a long range field similar to electromagnetic field, the particle and antiparticle, possessing that charge, can form primordial bound system with annihilation timescale, which can satisfy the conditions, assumed for this type of UHECR sources. These conditions severely constrain the possible properties of considered particles.

astro-ph↗

arXiv2002

Strong Primordial Inhomogeneities and Galaxy Formation

The new element of theory of galaxy formation, strong primordial inhomogeneities, is shown to be a reflection of unstable large scale structures of topological defects, created in second order phase transitions in the inflationary Universe. In addition to {\it archioles-like} large scale correlation of the primordial inhomogeneity of energy density of coherent scalar field oscillations, the same mechanism, based on the second order phase transitions on the inflational stage and the domain wall formation upon the end of inflation, leads to the formation of massive black hole clusters that can serve as nuclei for the future galaxies. The number of black holes with $M \sim 100M_{\odot}$ and above is comparable with the number of galaxies within the modern cosmological horizon. The primordial fractal structure of galaxies can find natural grounds in the framework of model we developed . The proposed approach offers the physical basis for new scenarios of galaxy formation in the Big Bang Universe.

astro-ph↗

arXiv2002

Cosmoparticle physics - the Challenge to the Millenium

Cosmoparticle physics offers the exciting challenge for the new Millenium to come to the true knowledge on the basic natural laws and on the way, they govern the creation and evolution of the Universe with all the forms of its present energy content. The theory of everything, the true history of the Universe, based on it, the new sources of energy release and the new means of energy transfer should come from the prospects of cosmoparticle physics. We may be near the first positive results in this direction. The methods of cosmoparticle physics are briefly reviewed.

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arXiv2002

Implications of a solar-system population of massive 4th generation neutrinos for underground searches of monochromatic neutrino-annihilation signals

It has been recently pointed out that any primary galactic population of Weakly Interacting Massive Particles (WIMP) generates, through collisions with solar matter, a secondary population of ``slow'' WIMPs trapped in the inner solar system. We show that taking into account this ``slow'' solar-system population dramatically enhances the possibility to probe the existence of stable massive neutrinos (of a 4th generation) in underground neutrino experiments. Our work suggests that a reanalysis of existing underground neutrino data should be able to bring extremely tight constraints on the possible existence of a stable massive 4th neutrino.

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arXiv2000

Primordial Black Holes from Non-Equilibrium Second Order Phase Transition

The collapse of sufficiently large closed domain wall produced during second order phase transition in the vacuum state of a scalar field can lead to the formation of black hole. The origin of domain walls with appropriate size and energy density could be a result of evolution of an effectively massless scalar field at the inflational epoch. We demonstrate that in this case the situation is valued when there are compact domains of less favorable vacuum surrounded by a sea of another vacuum. Each domain has a surface composed of vacuum wall that stores a significant amount of energy, and can collapse into the black hole. This offers the way of massive primordial black holes formation in the early Universe.

hep-ph↗

arXiv2000

Antiprotons Annihilation in the Galaxy As A Source of Diffuse Gamma Background

The existence of antimatter domains in baryon asymmetrical Universe can appear as the cosmological consequence of particle theory in inflationary models with non-homogeneous baryosynthesis. Such a domain can survive in the early Universe and form globular cluster of antimatter stars in our Galaxy. The model of antimatter pollution of Galaxy and annihilation with matter gas is developed. The proton-antiproton annihilation gamma flux is shown to reproduce the observed galactic gamma background measured by EGRET. From comparison with observational data the estimation on the maximally allowed amount of antimatter stars, possibly present in our Galaxy, is found.

astro-ph↗

arXiv1999

First Order Phase Transitions as a Source of Black Holes in the Early Universe

A new mechanism of black hole formation in a first order phase transition is proposed. In vacuum bubble collisions the interaction of bubble walls leads to the formation of nontrivial vacuum configuration. The consequent collapse of this vacuum configuration induces the black hole formation with high probability. The primordial black holes that have been created by this way at the end of first order inflation could give essential contribution into the total density of the early Universe. The possibilities to establish some nontrivial restrictions on the inflation models with first order phase transition are discussed.

hep-ph↗

arXiv1999

Diffuse Gamma Flux from Antiproton Annihilation in our Galaxy

The all-sky survey in high-energy gamma rays (E > 30 MeV) carried out by the Energetic Gamma Ray Experiment Telescope (EGRET) aboard the Compton Gamma-Ray Observatory provides a unique opportunity to examine in detail the diffuse gamma-ray emission. The observed diffuse emission has a Galactic component arising from cosmic-ray interactions with the local interstellar gas and radiation as well an almost uniformly distributed component that is generally believed to originate outside the Galaxy. The results of the observations have been interpreted as the extragalactic high-energy gamma-ray emission arising primarily from unresolved gamma-ray-emitting blazars. We considered another possible origin of the diffuse gamma-ray flux, namely, as originating from the annihilation of the antiprotons with the interstellar medium.

astro-ph↗

arXiv1999

Possible Effects of the Existence of the 4th Generation Neutrino

The 4th generation of fermions predicted by the phenomenology of heterotic string models can possess new strictly conserved charge, which leads, in particular, to the hypothesis of the existence of the 4th generation massive stable neutrino. The compatibility of this hypothesis with the results of underground experiment DAMA searching for weakly interactive particles of dark matter and with the EGRET measurements of galactic gamma--background at energies above 1 GeV fixes the possible mass of the 4th neutrino at the value about 50 GeV. The possibility to test the hypothesis in accelerator experiments is considered. Positron signal from the annihilation of relic massive neutrinos in the galactic halo is calculated and is shown to be accessible for planned cosmic ray experiments.

astro-ph↗

arXiv1999

AMS-Shuttle test for antimatter stars in our Galaxy

The AMS--Shuttle experiment is shown to be sensitive to test the hypothesis on the existence of antimatter globular cluster in our Galaxy. The hypothesis follows from the analysis of possible tests for the mechanisms of baryosynthesis and uses antimatter domains in the matter dominated Universe as the probe for the physics underlying the origin of the matter. The total mass for the antimatter objects in our Galaxy is fixed from the below by the condition of antimatter domain survival in the matter dominated Universe and from above by the observed gamma ray flux. For this mass interval the expected fluxes of antinuclei can lead to up to ten antihelium events in the AMS-Shuttle experiment.

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