B-ball Baryogenesis and D-term Inflation

Abstract

The MSSM has flat directions in its scalar potential, along which it is natural for Bose condensates of squarks to form in the early Universe. A baryon asymmetry can be induced in these condensates via Affleck-Dine baryogenesis. The condensates are unstable with respect to fragmentation to "B-balls", solitons made of squarks and carrying baryon number, which, if they survive thermalization, fill the Universe down to low temperatures, much lower than that of the electroweak phase transition, with interesting cosmological consequences. In particular, their decay implies a similar number density of baryons and dark matter neutralinos, in accordance with observations. Evasion of thermalization and the ability to account for the observed baryon asymmetry requires a very low reheating temperature, which, it is argued, is a natural feature of presently favoured D-term inflation models.