Q-ball Evolution, B-ball Baryogenesis and the f_(B) Problem

We consider some of the issues surrounding the formation and evolution of Q-balls in the MSSM and its extensions. The ratio of the baryon number packed into Q-balls to that outside, f_{B}, plays a fundamental role in determining the relationship of dark matter to the baryon number in the Universe at present. The final value of f_{B} will depend upon the details of the formation of Q-balls from the collapse of the Affleck-Dine condensate and upon the subsequent evolution of the ensemble of Q-balls. We discuss the implications for neutralino dark matter in the gravity-mediated scenario and show that a light neutralino is necessary in most cases to account for the baryon to dark matter ratio, with an NMSSM singlino LSP of mass m_{\chi} \lae 20 \GeV being a favoured candidate.