97 research outputs found
The puzzles of dark matter searches
Positive results of dark matter searches in DAMA/NaI and DAMA/LIBRA
experiments, being put together with negative results of other groups, can
imply nontrivial particle physics solutions for cosmological dark matter.
Stable particles with charge -2 bind with primordial helium in O-helium "atoms"
(OHe), representing a specific Warmer than Cold nuclear-interacting form of
dark matter. Slowed down in the terrestrial matter, OHe is elusive for direct
methods of underground Dark matter detection like those used in CDMS
experiment, but its reactions with nuclei can lead to annual variations of
energy release in the interval of energy 2-6 keV in DAMA/NaI and DAMA/LIBRA
experiments. Schrodinger equation for system of nucleus and OHe is solved for
spherically symmetrical potential well, formed by the Yukawa tail of nuclear
scalar isoscalar attraction potential, acting on He beyond the nucleus, and
dipole Coulomb repulsion between the nucleus and OHe at distances from the
nuclear surface, smaller than the size of OHe. The window of parameters of this
potential is found, at which the sodium and/or iodine nuclei have a few keV
binding energy with OHe. At nuclear parameters, reproducing DAMA results, the
energy release predicted for detectors with chemical content other than NaI
differ in the most cases from the one in DAMA detector. In particular, it is
shown that in the case of CDMS the energy of OHe-germanium bound state is
beyond the range of 2-6 keV and its formation should not lead to ionization in
the energy interval of DAMA signal. (abridged)Comment: to be published in the AIP Proceedings of the 'Invisible Universe
International Conference', UNESCO-Paris, June 29-July 3, 2009; 10 pp., 6 Fig
Dark Atoms of Dark Matter and their Stable Charged Constituents
Direct searches for dark matter lead to serious problems for simple models
with stable neutral Weakly Interacting Massive Particles (WIMPs) as candidates
for dark matter. A possibility is discussed that new stable quarks and charged
leptons exist and are hidden from detection, being bound in neutral dark atoms
of composite dark matter. Stable -2 charged particles are bound with
primordial helium in O-helium (OHe) atoms, being specific nuclear interacting
form of composite dark matter. The positive results of DAMA experiments can be
explained as annual modulation of radiative capture of O-helium by nuclei. In
the framework of this approach test of DAMA results in detectors with other
chemical content becomes a nontrivial task, while the experimental search of
stable charged particles at LHC or in cosmic rays acquires a meaning of direct
test for composite dark matter scenario.Comment: Contribution to Proceedings of ICATPP201
Physics of Primordial Universe
The physical basis of the modern cosmological inflationary models with
baryosynthesis and nonbaryonic dark matter and energy implies such predictions
of particle theory, that, in turn, apply to cosmology for their test. It makes
physics of early Universe ambiguous and particle model dependent. The study of
modern cosmology is inevitably linked with the probe for the new physics,
underlying it. The particle model dependent phenomena, such as unstable dark
matter, primordial black holes, strong primordial inhomogeneities, can play
important role in revealing the true physical cosmology. Such phenomena, having
serious physical grounds and leading to new nontrivial cosmological scenarious,
should be taken into account in the data analysis of observational cosmology.Comment: 25.09.200
Fundamental Particle Structure in the Cosmological Dark Matter
The nonbaryonic dark matter of the Universe is assumed to consist of new
stable forms of matter. Their stability reflects symmetry of micro world and
mechanisms of its symmetry breaking. Particle candidates for cosmological dark
matter are lightest particles that bear new conserved quantum numbers. Dark
matter particles may represent ideal gas of non-interacting particles.
Self-interacting dark matter weakly or superweakly coupled to ordinary matter
is also possible, reflecting nontrivial pattern of particle symmetry in the
hidden sector of particle theory. In the early Universe the structure of
particle symmetry breaking gives rise to cosmological phase transitions, from
which macroscopic cosmological defects or primordial nonlinear structures can
be originated. Primordial black holes (PBHs) can be not only a candidate for
dark matter, but also represent a universal probe for super-high energy physics
in the early Universe. Evaporating PBHs turn to be a source of even superweakly
interacting particles, while clouds of massive PBHs can serve as a nonlinear
seeds for galaxy formation. The observed broken symmetry of the three known
families may provide a simultaneous solution for the problems of the mass of
neutrino and strong CP violation in the unique framework of models of
horizontal unification. The existence of new stable charged leptons and quarks
is possible, hidden in elusive "dark atoms". Such possibility, strongly
restricted by the constraints on anomalous isotopes of light elements, is not
excluded in scenarios that predict stable double charged particles. The
excessive -2 charged particles are bound in these scenarios with primordial
helium in O-helium "atoms", maintaining specific nuclear-interacting form of
the dark matter, which may provide an interesting solution for the puzzles of
the direct dark matter searches. (abridged)Comment: Invited review to International Journal of Modern Physics
Cosmoparticle Physics -the Challenge for the Millenium
Cosmoparticle physics is the natural result of development of mutual
relationship between cosmology and particle physics. Its prospects offer the
way to study the theory of everything and the true history of the Universe,
based on it, in the proper combination of their indirect physical,
astrophysical and cosmological signatures. We may be near the first positive
results in this direction. The basic ideas of cosmoparticle physics are briefly
reviewed.Comment: 19.09.200
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