2013/02/06 by A. D. Dolgov, Dolgov, A. D.
Physics and Astronomy · #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #astro-ph.CO #hep-ph
paper · pdf · doi:10.48550/arxiv.1302.1428
24 pages, in Russian, Lectures presented at the Summer School "Fundamental Interactions" organized by D. Zumin Foundation "Dinastiya"; Protvino, Russia, August, 2012
arxiv created 2013/02/06 · arxiv updated 2013/02/07
Several lectures for non-experts on equilibrium and non-equilibrium kinetics in expanding universe are presented. An establishment of thermal equilibrium in the ealry universe as well as mechanisms leading to deviations from the equilibrium are discussed. In the first lecture an elementary introduction to cosmology is presented. Next, kinetic equation in Friedman-Robertson-Walker mertric is considered. Properties of its solutions for different types of particles, in particular, for photons of cosmic microwave background radiation, neutrinos, and massive particles, which could be cold dark matter ones, are analyzed. It is shown, in particular, that despite being massless, neutrinos noticeably deviate from equilibrium. Next the modification of the detailed balance condition in the case of broken T-invariance is discussed and it is shown that the standard equilibrium distribution functions remain unchanged. Possible modification of the standard kinetics in the case of broken CPT and applications to baryogenesis are considered.