Heavy Axion Opportunities at the DUNE Near Detector

TL;DR

This paper demonstrates that the DUNE Near Detector can uniquely detect heavy axions in the 20 MeV to 2 GeV range, offering new opportunities for exploring axion-like particles beyond traditional light axion models.

Contribution

It provides a detailed analysis showing DUNE ND's sensitivity to heavy axions, highlighting its potential as a powerful beam dump experiment for this purpose.

Findings

DUNE ND can detect heavy axions between 20 MeV and 2 GeV.

DUNE ND's sensitivity is complementary to other future experiments.

Heavy axions can solve the Strong CP and axion Quality Problems.

Abstract

While the QCD axion is often considered to be necessarily light ($\lesssim$ eV), recent work has opened a viable and interesting parameter space for heavy axions, which solve both the Strong CP and the axion Quality Problems. These well-motivated heavy axions, as well as the generic axion-like-particles, call for explorations in the GeV mass realm at collider and beam dump environments. The primary upcoming neutrino experiment, Deep Underground Neutrino Experiment (DUNE), is simultaneously also a powerful beam dump experiment, enabled by its multipurpose Near Detector (ND) complex. In this study, we show with detailed analyses that the DUNE ND has a unique sensitivity to heavy axions for masses between $20$ MeV and $2$ GeV, complementary to other future experiments.