Speakers
Description
Among cosmological relaxation solutions to the weak-scale hierarchy problem, gauge boson production is a particularly efficient backreaction mechanism for trapping the relaxion. In these models, scanning can even happen after inflation and the relaxion field range can be sub-Planckian, with no extremely small parameters or large e-foldings involved. We consider a model where particle production by the relaxion also reheats the universe and generates the baryonic matter-antimatter asymmetry. Out-of-equilibrium leptons, produced by the relaxion or from the hidden sector, scatter with the thermal bath through interactions that violate CP and lepton number via higher-dimensional operators. Such an effective field theory setup, with no new physics below the cut-off, is sufficient to achieve successful leptogenesis by the relaxion. The baryon asymmetry is thus intrinsically tied to a weak-scale hierarchy.
