Pure Gravity Mediation and Chaotic Inflation in Supergravity

TL;DR

This paper explores how pure gravity mediation can be compatible with chaotic inflation in supergravity, highlighting the role of an approximate Z2 symmetry in suppressing gravitino overproduction and favoring a gravitino mass around 100 TeV.

Contribution

It demonstrates the utility of an approximate Z2 parity in supergravity models to reconcile chaotic inflation with pure gravity mediation, addressing gravitino and dark matter production issues.

Findings

Approximate Z2 parity suppresses gravitino production.

Large gravitino mass (~100 TeV) avoids overproduction of LSP.

Parameter tuning needed for lower gravitino masses.

Abstract

We investigate compatibility of the pure gravity mediation (or the minimal split supersymmetry) with chaotic inflation models in supergravity. We find that an approximate Z2 parity of the inflaton is useful to suppress gravitino production from thermal bath and to obtain consistent inflation dynamics. We discuss production of the lightest supersymmetric particle through the decay of the inflaton with the approximate Z2 symmetry and find that a large gravitino mass is favored to avoid the overproduction of the lightest supersymmetric particle, while a lower gravitino mass requires tuning of parameters. This may explain why the nature has chosen the gravitino mass of O(100) TeV rather than O(100) GeV.