Inverse Primakoff Scattering as a Probe of Solar Axions at Liquid Xenon Direct Detection Experiments

TL;DR

This paper demonstrates that liquid xenon direct detection experiments can effectively probe solar axions via inverse-Primakoff scattering, significantly enhancing sensitivity to axion-photon couplings and expanding the accessible parameter space.

Contribution

It introduces inverse-Primakoff scattering as a key detection channel in LXe experiments, improving sensitivity to axions and broadening the viable parameter space for solar axion searches.

Findings

Sensitivity to $g_{a\gamma}$ extends to $10^{-10}$ GeV$^{-1}$ for axion masses up to 1 keV.

The method can explain the XENON1T excess with solar axions within allowed parameter space.

Future LXe detectors can surpass helioscope experiments like IAXO in sensitivity.

Abstract

We show that XENON1T and future liquid xenon (LXe) direct detection experiments are sensitive to axions through the standard $g_{a\gamma}aF\tilde{F}$ operators due to inverse-Primakoff scattering. This previously neglected channel significantly improves the sensitivity to the axion-photon coupling, with a reach extending to $g_{a\gamma} \sim 10^{-10}$ GeV$^{-1}$ for axion masses up to a keV, thereby extending into the region of heavier QCD axion models. This result modifies the couplings required to explain the XENON1T excess in terms of solar axions, opening a large region of $g_{a\gamma}$ - $m_a$ parameter space which is not ruled out by the CAST helioscope experiment and reducing the tension with the astrophysical constraints. We explore the sensitivity to solar axions for future generations of LXe detectors which can exceed future helioscope experiments, such as IAXO, for a large region of parameter space.