Theory: Baryon asymmetry from particle production during axion inflation

by Kai Schmitz (CERN)

Monday 27 Feb 2023, 15:00 → 16:00 Europe/Berlin

SR2

Leptogenesis is an attractive mechanism to explain the baryon asymmetry of the Universe that typically relies on the simultaneous violation of baryon-minus-lepton number (B-L) and charge-parity invariance (CP). Recently, it has, however, been shown how standard leptogenesis can be generalized to arbitrary chemical backgrounds in the early Universe, such that the dynamics of CP and B-L violation are no longer necessarily related to each other. The central idea of this scenario, dubbed "wash-in leptogenesis", is that right-handed-neutrino interactions assume the status of spectator processes and are responsible as such for converting primordial charge asymmetries generated at high temperatures to a new B-L-violating chemical equilibrium at low temperatures. In this talk, I will first review the basics of wash-in leptogenesis and then explain how cosmic inflation driven by an axion-like pseudoscalar field that couples to the Standard Model hypercharge gauge sector can provide the right initial conditions for wash-in leptogenesis. This talk is based on work in collaboration with Valerie Domcke, Eduard Gorbar, Kohei Kamada, Kyohei Mukaida, Oleksandr Sobol, Stanislav Vilchinskii, and Masaki Yamada [2011.09347, 2109.01651, 2111.04712, 2210.06412].