New one-parametric extension of the Starobinsky inflationary model

TL;DR

This paper introduces a one-parameter extension to the Starobinsky inflation model by adding a new term, resulting in a model with potentially larger tensor-to-scalar ratios that remains consistent with current observations.

Contribution

It presents a novel one-parametric extension of the Starobinsky model with a new term, analyzing its inflationary predictions and observational viability.

Findings

Tensor-to-scalar ratio can be significantly larger.

Model remains consistent with observational data.

Scalar potential is a polynomial of exponential functions.

Abstract

We propose a one-parametric extension of the Starobinsky $R+R^2$ model by adding the $(R+m^2\beta^2)^{3/2}$ term. The parameter $m$ is the inflaton mass, which is determined in the same way as in the Starobinsky model, and $\beta$ is a dimensionless constant. Using the Einstein frame and the scalar field potential, we get the inflationary parameters of the model proposed. The value of the tensor-to-scalar ratio $r$ can be significantly larger than in the Starobinsky model. The considered inflationary model is in a good agreement with the current observational data. The corresponding scalar field potential is a polynomial of the exponential function.