Grant: Subatomic Physics Envelope - Individual

There are fundamental links between cosmology and particle physics, which have been well established at all scales. In particular, the physics of the early Universe, baryogenesis, cosmological nucleosynthesis, etc. is based on our modern understanding of particle physics. This realization has made the early Universe a marvelous laboratory for studying fundamental physics, in particular the vacuum structure of the theory. Conversely, knowledge of the behavior of fundamental physics at high temperature gives information about what happened shortly after the Big Bang. What is more remarkable is the fact that these phenomena at the QCD scale can be, in principle, experimentally tested in heavy ion collisions at RHIC (relativistic heavy ion collider), Brookhaven National Labaratory, and in the nearest future at LHC (Geneva, Switzerland) where such unusual environment can be achieved. The goal of the project is: the study of QCD as part of the standard model in an unusual environment when temperature T, chemical potential and the so-called theta- parameter are non-zero. This knowledge gives a reliable information about what have happened 14 billion years ago soon after the Big Bang at the temperature T = 170 MeV. The understanding of the corresponding phase diagram (as a function of these external parameters) is one of the most challenging problems in QCD. This problem with nonzero theta parameter has never been studied previously in the literature, though it is likely that theta parameter was non-zero during the QCD phase transition few moments after the Big Bang. Due to the differences in interactions between quarks and antiquarks in the presence of the theta parameter the local separation of baryon charges may take place. This phenomenon can be tested at RHIC. In fact, the phenomenon of charge separation has been studied in our recent paper with D. Kharzeev. What is more important: this effect has been experimentally tested at RHIC. Preliminary results support our findings. If confirmed, it would be the first ever observation of the P and CP violation in strong interactions. Second part of the project is the application of the ideas mentioned above for needs of astrophysics and cosmology.