Search for solar axions with mass around 1 eV using coherent conversion of axions into photons

A search for solar axions has been performed using an axion helioscope which is equipped with a 2.3-m long 4 T superconducting magnet, a gas container to hold dispersion-matching gas, PIN-photodiode X-ray detectors, and a telescope mount mechanism to track the sun. A mass region around m(a) = 1 eV was newly explored. From the absence of any evidence, analysis sets a limit on axion-photon coupling constant to be g(a gamma gamma) < 5.6-13.4 x 10(-10) GeV-1 for the axion mass of 0.84 < m(a) < 1.00 eV at 95% confidence level. It is the first result to search for the axion in the g(a gamma gamma)-m(a) parameter region of the preferred axion models with a magnetic helioscope. (C) 2008 Elsevier B.V. All rights reserved.