Nonminimal Inflation in Supersymmetric GUTs with $U(1)_R \times Z_n$ Symmetry

TL;DR

This paper develops a supersymmetric hybrid inflation model with $U(1)_R imes Z_n$ symmetry, compatible with GUTs, avoiding monopole issues, and matching Planck 2018 observational data.

Contribution

It introduces a non-minimal inflation framework within SUSY GUTs using $U(1)_R imes Z_n$ symmetry, addressing monopole problems and aligning with observational constraints.

Findings

Predicted scalar spectral index $n_s$ between 0.960 and 0.966.

Tensor-to-scalar ratio $r$ between 0.0031 and 0.0045.

Model is consistent with Planck 2018 data.

Abstract

A supersymmetric hybrid inflation framework is employed to realize a class of non-minimal inflation models with $U(1)_R \times Z_n$ global symmetry. This framework naturally incorporates models based on grand unified theories by avoiding the most commonly faced monopole problem. The predictions of inflationary observables, the scalar spectral index $n_s = 0.960-0.966$ and the tensor to scalar ratio $r=0.0031-0.0045$, are in perfect agreement with the Planck 2018 data. For sub-Planckian values of the field the $Z_n$ symmetry is only allowed for $n\leq 4$.