# ALP inflation and Big Bang on Earth

## TL;DR

This paper explores a hilltop inflation model with an axion-like particle as the inflaton, linking cosmological inflation parameters to potential experimental searches for ALPs at ground-based experiments.

## Contribution

It establishes a specific relation between ALP mass and decay constant that explains CMB normalization and connects inflationary physics with laboratory searches.

## Key findings

- ALP decay constant and mass relation $m_\phi \sim 10^{-6} f$ explains CMB data.
- ALP can be detected in beam dump experiments like SHiP if inflation scale is low.
- The model links Big Bang cosmology to potential terrestrial experiments.

## Abstract

We study a hilltop inflation model where an axion-like particle (ALP) plays the role of the inflaton. We find that, for a broad class of potentials, the decay constant and the mass at the potential minimum satisfy the relation, $m_\phi \sim 10^{-6} f$, to explain the CMB normalization. The ALP is necessarily coupled to the standard model particles for successful reheating. The ALP with the above relation can be searched at beam dump experiments, e.g., the SHiP experiment, if the inflation scale is sufficiently low. In this case, the ALP decays through the interactions that led to the reheating of the Universe. In other words, the Big Bang may be probed at ground-based experiments.