Observational physics of mirror world

The existence of the whole world of shadow particles, interacting with each other and having no mutual interactions with ordinary particles except gravity is a specific feature of modern superstring models, being considered as models of the theory of everything. The presence of shadow particles is the necessary condition in the superstring models, providing compensation of the asymmetry of left and right chirality states of ordinary particles. If compactification of additional dimensions retains the symmetry of left and right states, shadow world turns to be the mirror one, with particles and fields having properties strictly symmetrical to the ones of corresponding ordinary particles and fields. Owing to the strict symmetry of physical laws for ordinary and mirror particles, the analysis of cosmological evolution of mirror matter provides rather definite conclusions on possible effects of mirror particles in the universe. A general qualitative discussion of possible astronomical impact of mirror matter is given, in order to make as wide as possible astronomical observational searches for the effects of mirror world, being the unique way to test the existence of mirror partners of ordinary particles in the Nature

Orbifold Family Unification

We study the possibility of complete family unification in higher-dimensional space-time. Three families of matters in SU(5) grand unified theory are derived from a single bulk multiplet of SU(N) gauge group (N >= 9) in the framework of S^1/Z_2 orbifold models. In the case of the direct orbifold breaking down to the standard model gauge group, there are models in which bulk fields from a single multiplet and a few brane fields compose three families of quarks and leptons.Comment: Comments added, version to appear in Physical Review D (v3); References added (v2); 19 pages (v1

Signature of relic heavy stable neutrinos in underground experiments

Considering heavy stable neutrinos of 4th generation we calculate the relic density of such neutrinos in the Universe. Taking into account the condensation of heavy neutrinos in the Galaxy and applying the results of calculations to experimental data from underground experiments on search for WIMPs in elastic neutral current scattering on nuclei we found an exclusion region of neutrino mass 60 GeV < m < 290 GeV. The bounds obtained from present underground experiments while confirming the previous bounds derived from analysis of cosmic ray spectra are more relible ones. We discuss also the first indication of elastic scattering induced by WIMP in DAMA experiment finding a very narrow window of neutrino mass 45 GeV < m < 50 GeV compatible with the possible signal rate in the detector.Comment: 12 pages, 3 figure

The Formation of Primary Galactic Nuclei during Phase Transitions in the Early Universe

A new mechanism describing the formation of protogalaxies is proposed, which is based on the second- order phase transition in the inflation stage and the domain wall formation upon the end of inflation. The presence of closed domain walls with the size markedly exceeding the cosmological horizon at the instant of their formation and the wall collapse in the postinflation epoch (when the wall size becomes comparable with the cosmological horizon), which leads to the formation of massive black hole clusters that can serve as nuclei for the future galaxies. The black hole mass distributions obtained do not contradict the available experimental data. The number of black holes with M ~ 100 solar masses ($M_{\odot}$) and above is comparable with the number of Galaxies in the visible Universe. Development of the proposed approach gives ground for a principally new scenario of the galaxy formation in the model of hot Universe.Comment: 9 page

Gravitino production by primordial black hole evaporation and constraints on the inhomogeneity of the early Universe

In supergravity models, the evaporation of light Primordial Black Holes (PBHs) should be a source of gravitinos. By considering this process, new stringent limits are derived on the abundance of small black holes with initial masses less than 10^9 g. In minimal supergravity, the subsequent decay of evaporated gravitinos into cascades of non-equilibrium particles leads to the formation of elements whose abundance is constrained by observations. In gauge mediated supersymmetry breaking models, their density is required not to overclose the Universe. As a result, cosmological models with substantial inhomogeneities on small scales are excluded.Comment: Published version. Minor changes, references adde

Testing Primordial Abundances With Sterile Neutrinos

The mixing between sterile and active neutrinos is taken into account in the calculation of Big Bang Nucleosynthesis. The abundances of primordial elements, like D, 3He, 4He and 7Li, are calculated by including sterile neutrinos, and by using finite chemical potentials. It is found that the resulting theoretical abundances are consistent with WMAP data on baryonic densities, and with limits of LSND on mixing angles, only if 7Li is excluded from the statistical analysis of theoretical and experimental results.Comment: 7 pages, 3 figures, 1 table, 34 reference