Search for solar axions in XMASS, a large liquid-xenon detector

TL;DR

This study used the XMASS liquid-xenon detector to search for solar axions, setting new limits on axion-electron coupling and axion mass, surpassing previous experimental and astrophysical bounds.

Contribution

First direct experimental search for solar axions using a large liquid-xenon detector, providing the most stringent limits in certain mass ranges.

Findings

Set a model-independent limit on axion-electron coupling: |g_{aee}|< 5.4×10^{-11}

Established upper bounds on axion masses for DFSZ and KSVZ models: 1.9 eV and 250 eV

Achieved the most stringent limit in the 10-40 keV mass range to date.

Abstract

XMASS, a low-background, large liquid-xenon detector, was used to search for solar axions that would be produced by bremsstrahlung and Compton effects in the Sun. With an exposure of 5.6ton days of liquid xenon, the model-independent limit on the coupling for mass $\ll$ 1keV is $|g_{aee}|< 5.4\times 10^{-11}$ (90% C.L.), which is a factor of two stronger than the existing experimental limit. The bounds on the axion masses for the DFSZ and KSVZ axion models are 1.9 and 250eV, respectively. In the mass range of 10-40keV, this study produced the most stringent limit, which is better than that previously derived from astrophysical arguments regarding the Sun to date.