Center for Theoretical Physics of the Universe (CTPU)

Leptogenesis in cosmological relaxation with particle production

by Dr Fang Ye

CTPU Seminar Room

CTPU Seminar Room

Fourth floor IBS Building, 55, Expo-ro, Yuseong-gu, Daejeon, Korea, 34126

We discuss a scenario that intrinsically connects leptogenesis to the cosmological relaxation of electroweak scale. Relaxation scanning ends after inflation, with a sub-Planckian field excursion and a cutoff up to 10^5 GeV. Particle production by the relaxion has not only been used to trap the relaxion in a local minimum, picking up a correct electroweak vacuum, but also reheated the universe, providing the thermal bath and out-of-equilibrium leptons. Out-of-equilibrium leptons scatter with the thermal leptons through interactions that violate CP and lepton number symmetry via higher dimensional operators. We show that with sufficient parameter space, an order of 10^-10 baryon asymmetry can be generated. Such models have many nice features. There is no extremely small parameter or large number of e-folds. The models serve as a minimal effective field theory to realize leptogenesis in electroweak cosmological relaxation, with no new physics below the cutoff, and naturally decouples the new physics while linking baryon asymmetry to the particle production by the relaxion.