Inflation connected to the origin of $CP$ violation

TL;DR

This paper proposes a simple extension of the standard model linking the origin of $CP$ violation to inflation through singlet scalars, addressing $CP$ issues and early universe dynamics.

Contribution

It introduces singlet scalars with nonminimal coupling to Ricci scalar that simultaneously explain $CP$ violation and serve as inflaton candidates, connecting particle physics and cosmology.

Findings

Singlet scalars can induce spontaneous $CP$ violation at low energies.

The model provides a candidate for inflaton with suitable nonminimal coupling.

Reheating and leptogenesis are affected by the singlet scalars in this framework.

Abstract

We consider a simple extension of the standard model, which could give a solution for its $CP$ issues such as the origin of both CKM and PMNS phases and the strong $CP$ problem. The model is extended with singlet scalars which could cause spontaneous $CP$ violation to result in these phases at low energy regions. The singlet scalars could give a good inflaton candidate if they have a suitable nonminimal coupling with the Ricci scalar. $CP$ issues and inflation could be closely related through these singlet scalars in a natural way. In a case where inflaton is a mixture of the singlet scalars, we study reheating and leptogenesis as notable phenomena affected by the fields introduced in this extension.