1,918 research outputs found
Gravitational particle production in braneworld cosmology
Gravitational particle production in time variable metric of an expanding
universe is efficient only when the Hubble parameter is not too small in
comparison with the particle mass. In standard cosmology, the huge value of the
Planck mass makes the mechanism phenomenologically irrelevant. On the
other hand, in braneworld cosmology the expansion rate of the early universe
can be much faster and many weakly interacting particles can be abundantly
created. Cosmological implications are discussed.Comment: 4 pages, 1 figure, v3 with new definition of and minor text
modification
Matter-antimatter domains in the universe
A possible existence of cosmologically large domains of antimatter or
astronomical ``anti-objects'' is discussed. A brief review of different
scenarios of baryogenesis predicting a noticeable amount of antimatter is
given. Though both theory and observations indicate that the universe is most
possibly uniformly charge asymmetric without any noticeable amount of
antimatter, several natural scenarios are possible that allow for
cosmologically (astronomically) interesting objects in close vicinity to us.
The latter may be discovered by observation of cosmic ray antinuclei.Comment: Invited Talk at EuroConference on Frontiers in Particle Astrophysics
and Cosmology, San Feliu de Guixols, Spain, 30 September - 5 October 2000; 7
pages; latex; two references are adde
Baryogenesis, 30 Years after
A review of the basic principles of baryogenesis is given. Baryogenesis in
heavy particle decays as well as electroweak, SUSY-condensate, and spontaneous
baryogenesis are discussed. The models of abundant creation of antimatter in
the universe are briefly reviewed.Comment: 30 pages, latex twic
Cosmic antimatter: models and phenomenology
The possibility of creation of cosmologically significant antimatter are
analyzed in different scenarios of baryogenesis. It is argued that there may
exist plenty of antimatter even in our Galaxy. Possible forms of antimatter
objects and their observational signatures are discussed.Comment: 6 pages; invited talk at 14th Lomonosov Conference, Moscow
University, August, 200
Cosmological Constraints on Neutrino Masses and Mixings
The bounds on neutrino masses and mixing that follows from the data on light
element abundances, large scale structure formation, and angular fluctuations
of cosmic microwave background radiation are analyzed. The role of neutrino
oscillations in BBN and the bounds on cosmological lepton asymmetry are
discussed.Comment: Talk presented at the NOON 2003 workshop, February 10-14, 2003,
Kanazawa, Japan (to be published in the Proceedings), 10 page
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