Wash-in leptogenesis after axion inflation

Understand

CP violation and the violation of baryon-minus-lepton number B-L do not necessarily have to occur simultaneously in order to accomplish successful leptogenesis.

• Instead, it suffices if new CP-violating interactions at high energies result in primordial charge asymmetries, which are then reprocessed into a nonvanishing B-L asymmetry by right-handed neutrinos (RHNs) at lower energies.
• In this paper, we study this novel mechanism known as "wash-in leptogenesis", utilizing axion inflation as the source of high-scale CP violation.
• We specifically consider axion inflation coupled to the Standard Model hypercharge sector, which results in the dual production of hypermagnetic helicity and fermionic charge asymmetries.