Kohei Kamada (RESCEU, U. Tokyo)

3:30pm Wednesday April 27, 2022

Magnetogenesis, Baryogenesis, and Wash-in Leptogenesis in Pseudoscalar Inflation

Pseudoscalar inflation or axion inflation is one of the most well-motivated models of inflation because the approximate shift symmetry guarantees the flatness of the potential against the quantum corrections. The CP and shift symmetric properties of pseudoscalar inflaton allows it to have a coupling to the Chern-Pontryagin density of the gauge fields. In this talk, I will argue that if the inflaton has such a coupling to the hyper U(1) gauge fields in the Standard Model, it can give a significant impact on the baryon asymmetry of the Universe. Namely, through the chiral anomaly, baryon asymmetry is directly produced at the end of inflation together with the helical magnetic fields. Although this asymmetry suffers from the sphaleron washout, decoupling of relatively light right-handed neutrinos will prevent the asymmetry from being washed out completely through the recently proposed mechanism, dubbed as the “wash-in” process. Moreover, the hypermagnetic helicity decay at the electroweak symmetry breaking give additional contributions to the baryon asymmetry of the Universe. I will explain some details of relevant phenomena in the scenario.