# Starobinsky-like Inflation, Supercosmology and Neutrino Masses in No-Scale Flipped SU(5)

## TL;DR

This paper embeds a flipped SU(5) GUT model within no-scale supergravity, predicting inflationary observables similar to Starobinsky's model, and explores implications for neutrino masses and early universe dynamics.

## Contribution

It introduces a novel integration of flipped SU(5) GUT with no-scale supergravity, analyzing its inflationary predictions and effects on neutrino masses and reheating processes.

## Key findings

- Inflationary predictions align with Starobinsky model.
- Model constrains scalar spectral index $n_s$.
- Strong reheating is favored to preserve baryon asymmetry.

## Abstract

We embed a flipped ${\rm SU}(5) \times {\rm U}(1)$ GUT model in a no-scale supergravity framework, and discuss its predictions for cosmic microwave background observables, which are similar to those of the Starobinsky model of inflation. Measurements of the tilt in the spectrum of scalar perturbations in the cosmic microwave background, $n_s$, constrain significantly the model parameters. We also discuss the model's predictions for neutrino masses, and pay particular attention to the behaviours of scalar fields during and after inflation, reheating and the GUT phase transition. We argue in favor of strong reheating in order to avoid excessive entropy production which could dilute the generated baryon asymmetry.