# ICHEP2018 SEOUL

Jul 4 – 11, 2018
COEX, SEOUL
Asia/Seoul timezone

## Leptogenesis in Cosmological Relaxation with Particle Production

Jul 5, 2018, 2:00 PM
15m
104 (COEX, Seoul)

### 104

#### COEX, Seoul

Parallel Astro-particle Physics and Cosmology

### Speakers

Dr Fang Ye (KAIST)Dr Fang Ye (KAIST)

### 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 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. The baryon asymmetry is thus intrinsically tied to a weak-scale hierarchy.

### Primary authors

Dr Fang Ye (KAIST) Tevong You (University of Cambridge) Prof. Minho Son (KAIST)