Electron EDM and soft leptogenesis in supersymmetric B-L extension of the standard model

Abstract

We analyze the connection between electric dipole moment of the electron and the soft leptogenesis in supersymmetric $B-L$ extension of the standard model. In this model, the $B-L$ symmetry is radiatively broken at TeV scale. Therefore, it is a natural framework for low scale seesaw mechanism and also for implementing the soft leptogenesis. We show that the phases of trilinear soft SUSY breaking couplings $A$, which are relevant for the lepton asymmetry, are not constrained by the present experimental bounds on electric dipole moment. As in the MSSM extended with right-handed neutrinos, successful leptogenesis requires small bilinear coupling $B$, which is now given by $A_N$ and $B-L$ breaking VEVs. SUSY $B-L$ model with non-universal $A$-terms such that $A_N=0$ while $A_{\nu }\ne 0$ is a promising scenario for soft leptogenesis. The proposed EDM experiments will test this scenario in the future.

Comments: 21 pages, 4 figures, minor changes, published version