Superradiant Leptogenesis

Abstract

We investigate how superradiance affects the generation of baryon asymmetry in a universe with rotating primordial black holes, considering a scenario where a scalar boson is coupled to the heavy right-handed neutrinos. We identify the regions of the parameter space where the scalar production is enhanced due to superradiance. This enhancement, coupled with the subsequent decay of the scalar into right handed neutrinos, results in the non-thermal creation of lepton asymmetry. We show that successful leptogenesis is achieved for masses of primordial black holes in the range of order $O(0.1~{\rm g}) - O(10~{\rm g})$ and the lightest of the heavy neutrino masses, $M_N \sim O(10^{12})~{\rm GeV}$. Consequently, regions of the parameter space, which in the case of Schwarzchild PBHs were incompatible with viable leptogenesis, can produce the observed matter-antimatter asymmetry.