Inflation in supergravity without Kahler potential

TL;DR

This paper introduces a novel supergravity inflation model utilizing higher derivative terms, avoiding the eta problem by excluding the inflaton from the Kähler potential and instead using a supersymmetric derivative term.

Contribution

It presents a new class of supergravity inflation models where the inflaton is not in the Kähler potential, solving the eta problem with higher derivative terms.

Findings

Inflation driven by a single scalar field with standard kinetic term

No eta problem in these models

Effective scalar potential generated without inflaton in Kähler potential

Abstract

We propose a new class of inflation models in supergravity with higher derivative terms. In those models, the K\"ahler potential does not contain the inflaton multiplet, but a supersymmetric derivative term does. In the models, inflation is effectively driven by a single scalar field with a standard kinetic term and a scalar potential. Remarkably, the so-called $\eta$ problem does not exist in our models.