First Constraints on Heavy QCD Axions with a Liquid Argon Time Projection Chamber using the ArgoNeuT Experiment

TL;DR

This paper reports the first experimental constraints on heavy QCD axions in the 0.2-0.9 GeV mass range using the ArgoNeuT liquid argon detector, focusing on their decay into dimuon pairs.

Contribution

It provides the first constraints on heavy QCD axions in a previously unexplored mass range using a liquid argon TPC at Fermilab.

Findings

Set new 95% confidence level limits on heavy axions between 0.2-0.9 GeV.

Demonstrated the capability of ArgoNeuT and MINOS detectors to search for heavy axion decays.

Constrained axion decay constants around tens of TeV.

Abstract

We present the results of a search for heavy QCD axions performed by the ArgoNeuT experiment at Fermilab. We search for heavy axions produced in the NuMI neutrino beam target and absorber decaying into dimuon pairs, which can be identified using the unique capabilities of ArgoNeuT and the MINOS near detector. This decay channel is motivated by a broad class of heavy QCD axion models that address the strong CP and axion quality problems with axion masses above the dimuon threshold. We obtain new constraints at a 95\% confidence level for heavy axions in the previously unexplored mass range between 0.2-0.9 GeV, for axion decay constants around tens of TeV.