Symmetry non-restoration via order 10 −10 B and L asymmetries

Abstract

It has been observed that a large lepton asymmetry, n L / s≈0.1, can prevent the Higgs expectation value from going to zero at high temperature, resulting in the non-restoration of the SU(2)× U(1) gauge symmetry and other symmetries. This could allow for the elimination of domain walls and other dangerous topological defects. Here we show that if the reheating temperature after inflation, T R , is sufficiently low then symmetry non-restoration will occur with an asymmetry of the order of the observed baryon asymmetry, n B/ s≈10 −10. For this to occur T R≲1 GeV is necessary. Remarkably, this happens to be the reheating temperature expected in Affleck–Dine baryogenesis along a d=6 flat direction of the MSSM. As an example, we show that this can neatly solve the Z 3 domain wall problem of the NMSSM.