Chiral gravity waves and leptogenesis in inflationary models with non-Abelian gauge fields

Abstract

We present a leptogenesis scenario associated with inflationary models involving non-Abelian gauge fields within the standard model (SM) of particle physics. We show that this class of inflationary models generates intrinsic birefringent gravitational waves that following Alexander, Peskin, and Sheikh-Jabbari [Phys. Rev. Lett. 96, 081301 (2006)], through the gravitational chiral anomaly in the SM, can naturally create a net lepton number density. The $CP$-violating interaction is produced by tensor fluctuations of the gauge field, while the efficiency of this process is determined by the effective background value of the gauge field. We demonstrate that this mechanism can create the observed value of baryon to photon number density in a natural range of parameters of these models.