Polarized Gravitational Waves in Axion Inflation and the Origin of Baryon Asymmetry

by Azadeh Maleknejad (IPM Teheran)

Friday 29 Apr 2016, 11:30 → 12:30 Europe/Zurich

Room 234 (Geneva University)

In this talk, I will explain the effect of a non-Abelian gauge field with a small vev in the axion inflation models. The gauge field is coupled to the axion with a Chern-Simons interaction and has negligible effect on the background evolution. However, its quantum fluctuations make significant contribution to the cosmic perturbation. In particular, the gauge field has a spin-2 fluctuation which explicitly breaks the parity between the left- and right-handed polarization states. That chiral tensor modes are coupled to the gravitational waves and results in a polarized tensor power spectrum. From the gravitational anomaly in SM, our setup leads to the gravitational production of lepton number during inflation, sufficient enough to explain the observed matter asymmetry and the baryon to photon ratio.