Search for axion-like particles through nuclear Primakoff production using the GlueX detector

TL;DR

This paper reports the first search for axion-like particles via nuclear Primakoff production using the GlueX detector, setting limits on ALP coupling in the 200-450 MeV mass range with no evidence found.

Contribution

It introduces a novel search method for ALPs in the 200-450 MeV range using nuclear targets and the GlueX detector, providing new experimental bounds.

Findings

No evidence for ALPs was observed.

Limits on ALP coupling were set at the TeV scale.

Background from non-target-related processes was effectively estimated and subtracted.

Abstract

We report on the results of the first search for the production of axion-like particles (ALP) via Primakoff production on nuclear targets using the GlueX detector. This search uses an integrated luminosity of 100 pb$^{-1}\cdot$nucleon on a $^{12}$C target, and explores the mass region of 200 < $m_a$ < 450 MeV via the decay $X\rightarrow\gamma\gamma$. This mass range is between the $\pi^0$ and $\eta$ masses, which enables the use of the measured $\eta$ production rate to obtain absolute bounds on the ALP production with reduced sensitivity to experimental luminosity and detection efficiency. We find no evidence for an ALP, consistent with previous searches in the quoted mass range, and present limits on the coupling on the scale of $O$(1 TeV). We further find that the ALP production limit we obtain is hindered by the peaking structure of the non-target-related dominant background in GlueX, which we treat by using data on $^4$He to estimate and subtract these backgrounds. We comment on how this search can be improved in a future higher-statistics dedicated measurement.