# Primordial GWs from universality classes of pseudo-scalar inflation

## TL;DR

This paper explores how pseudo-scalar inflation models, especially Starobinsky-like, can produce observable gravitational waves detectable by current and future detectors, offering insights into inflation microphysics and primordial black holes.

## Contribution

It introduces a classification of inflationary models into universality classes and identifies the promising potential of Starobinsky-like models to generate detectable gravitational wave signals.

## Key findings

- Starobinsky-like models can produce observable GWs in upcoming detectors.
- The GW signals are detectable both in ground-based and space-based observatories.
- The mechanism may also contribute to primordial black hole formation.

## Abstract

In this contribution we discuss the possibility of generating an observable gravitational wave (GW) background by coupling a pseudo-scalar inflaton to some Abelian gauge fields. This analysis is performed by dividing inflationary models into universality classes. We find that of the most promising scenario is a Starobinsky-like model, which may lead to the generation of observational signatures both in upcoming CMB detectors as well as for direct GW detectors. The signal which can be produced in these models would both be observable in ground-based detectors, such as advanced LIGO, and in space-based detectors, such as LISA. The complementarity between the CMB and direct GW detection may be used to extract informations on the microphysics of inflation. Interestingly the mechanism discussed in this contribution may also be relevant for the generation of Primordial Black Holes (PBHs).