# Photoproduction of axion-like particles

## TL;DR

This paper investigates the potential of photon-beam experiments to detect axion-like particles (ALPs) with QCD-scale masses, introducing a new data-driven method to improve sensitivity and setting leading limits on ALP couplings.

## Contribution

It presents a novel data-driven approach to enhance ALP detection sensitivity and explores the potential of existing and future experiments like PrimEx and GlueX for ALP searches.

## Key findings

- PrimEx data could significantly improve ALP sensitivity in certain mass ranges.
- First study of photoproduction sensitivity for ALPs coupled to gluons.
- Set world-leading limits on ALP-gluon and ALP-photon couplings.

## Abstract

We explore the sensitivity of photon-beam experiments to axion-like particles (ALPs) with QCD-scale masses whose dominant coupling to the Standard Model is either to photons or gluons. We introduce a novel data-driven method that eliminates the need for knowledge of nuclear form factors or the photon-beam flux when considering coherent Primakoff production off a nuclear target, and show that data collected by the PrimEx experiment could substantially improve the sensitivity to ALPs with $0.03 \lesssim m_a \lesssim 0.3$ GeV. Furthermore, we explore the potential sensitivity of running the GlueX experiment with a nuclear target and its planned PrimEx-like calorimeter. For the case where the dominant coupling is to gluons, we study photoproduction for the first time, and predict the future sensitivity of the GlueX experiment using its nominal proton target. Finally, we set world-leading limits for both the ALP-gluon coupling and the ALP-photon coupling based on public mass plots.