Inflation and Leptogenesis in High-Scale Supersymmetry

TL;DR

This paper explores inflation and leptogenesis within high-scale supersymmetry frameworks, analyzing two supergravity models with different inflaton identifications, their mass spectra, and mechanisms for generating the universe's matter-antimatter asymmetry.

Contribution

It provides a detailed comparison of C-models and WZ-models in high-scale supersymmetry, including their inflationary dynamics, mass spectra, and leptogenesis mechanisms.

Findings

Reheating in C-models occurs via inflaton decay to Higgs bosons and right-handed neutrinos.

WZ-models achieve reheating through sneutrino decay, enabling leptogenesis.

The models' mass spectra and leptogenesis pathways depend on the gravitino mass relative to the inflation scale.

Abstract

No-scale supergravity provides a successful framework for Starobinsky-like inflation models. Two classes of models can be distinguished depending on the identification of the inflaton with the volume modulus, $T$ (C-models), or a matter-like field, $\phi$ (WZ-models). When supersymmetry is broken, the inflationary potential may be perturbed, placing restrictions on the form and scale of the supersymmetry breaking sector. We consider both types of inflationary models in the context of high-scale supersymmetry. We further distinguish between models in which the gravitino mass is below and above the inflationary scale. We examine the mass spectra of the inflationary sector. We also consider in detail mechanisms for leptogenesis for each model when a right-handed neutrino sector, used in the seesaw mechanism to generate neutrino masses, is employed. In the case of C-models, reheating occurs via inflaton decay to two Higgs bosons. However, there is a direct decay channel to the lightest right-handed neutrino which leads to non-thermal leptogenesis. In the case of WZ-models, in order to achieve reheating, we associate the matter-like inflaton with one of the right-handed sneutrinos whose decay to the lightest right handed neutrino simultaneously reheats the Universe and generates the baryon asymmetry through leptogenesis.