Gravitational Waves and Primordial Black Holes from Supersymmetric Hybrid Inflation

TL;DR

This paper explores a supersymmetric hybrid inflation model incorporating supergravity corrections, predicting primordial black holes and gravitational waves consistent with cosmological constraints and potentially explaining dark matter and NANOGrav signals.

Contribution

It introduces a specific inflation model with supergravity corrections that aligns with cosmological data and predicts observable primordial black holes and gravitational waves.

Findings

Model satisfies spectral index and tensor-to-scalar ratio constraints.

Predicts primordial black holes as dark matter candidates.

Forecasts gravitational wave signals detectable by future experiments.

Abstract

We study the effect of supergravity corrections due to a linear and a bilinear term in the K\"ahler potential, in the context of a supersymmetric hybrid inflation model. By appropriate choice of the parameters associated to these terms, we are able to satisfy the main cosmological constraints for the spectral index $n_s$ and the tensor-to-scalar ratio $r$. In addition, this model predicts primordial black hole abundance enough to account for the whole dark matter of the Universe and gravitational wave spectra within the reach of future detection experiments. The predictions of the model can be made compatible to the NANOGrav reported signal, at the cost of significantly lower primordial black hole abundance.