Q-ball metamorphosis

Flat directions in the minimal supersymmetric standard model are known to deform into nontopological solitons, Q balls, which generally possess both baryon and lepton asymmetries. We investigate how Q balls evolve if some of the constituent fields of the flat direction decay into light species. It is found that the Q balls takes a new configuration whose energy per charge slightly increases due to the decay. Specifically, we show that all the stable Q balls eventually transform into pure B balls via the decay into neutrinos.