The Tokyo Axion Helioscope Experiment

TL;DR

The paper reports on a solar axion search using a superconducting magnet helioscope at the University of Tokyo, setting new upper limits on axion-photon coupling for low-mass axions, surpassing previous solar age constraints.

Contribution

First solar axion search experiment with sensitivity to axion-photon coupling exceeding solar age limit constraints.

Findings

Set a 95% confidence level upper limit on $g_{a ightarrow ext{gamma}} < 6.0 imes 10^{-10} ext{GeV}^{-1}$ for $m_a < 0.03$ eV.

Demonstrated the effectiveness of the helioscope in probing low-mass axions.

Achieved the first sensitivity surpassing solar age considerations.

Abstract

A preliminary result of the solar axion search experiment at the University of Tokyo is presented. We searched for axions which could be produced in the solar core by exploiting the axion helioscope. The helioscope consists of a superconducting magnet with field strength of 4 Tesla over 2.3 meters. From the absence of the axion signal we set a 95 % confidence level upper limit on the axion coupling to two photons $g_{a\gamma\gamma} < 6.0 \times 10^{-10} GeV^{-1}$ for the axion mass $m_a < 0.03$ eV. This is the first solar axion search experiment whose sensitivity to $g_{a\gamma\gamma}$ exceeds the limit inferred from the solar age consideration.