Affleck-Dine baryo/leptogenesis with a gauged U(1)(B-L)

Abstract

We briefly review the present status of Affleck-Dine baryo/leptogenesis scenarios in the minimal supersymmetric standard model (MSSM) in the context of the gravity-mediated SUSY breaking, and show that there is a serious cosmological problem in the Affleck-Dine mechanism. That is, the late decay of the associated large Q-balls leads to the over production of the lightest supersymmetric particles. Then, we point out that the minimal extension of the MSSM by introducing a gauged $U(1)_{B-L}$ symmetry naturally solves this problem. Here, the breaking scale of the $U(1)_{B-L}$ can be determined quite independently of the reheating temperature from the required baryon asymmetry. It is extremely interesting that the obtained scale of the $U(1)_{B-L}$ breaking is well consistent with the one suggested from the seesaw mechanism to explain the recent neutrino-oscillation experiments. We consider that the present scenario provides a new determination of the $U(1)_{B-L}$ breaking scale fully independent of the neutrino masses. We also comment on viability of the present scenario in anomaly-mediated SUSY breaking models.