Remarks on Hubble Induced Mass from Fermion Kinetic Term

TL;DR

This paper investigates how fermion kinetic terms in supergravity during the radiation-dominated era induce an effective mass of the order of the Hubble scale for scalar fields interacting via Planck-suppressed couplings.

Contribution

It provides a detailed calculation of the fermion kinetic term's contribution to scalar mass in supergravity, highlighting its significance during the radiation era.

Findings

Fermion kinetic terms induce a Hubble-scale effective mass for scalars.

The effect is significant during the radiation-dominated era.

Planck-suppressed interactions can lead to sizable scalar masses.

Abstract

We evaluate the effective mass of a scalar field which interacts with visible sector via Planck-suppressed coupling in supergravity framework. We focus on the radiation-dominated (RD) era after inflation and the contribution from a fermionic field in the thermal bath. We find that, in RD era, the fermion kinetic term gives the effective mass of the order of Hubble scale to the scalar field.