Search for solar axions with CsI(Tl) crystal detectors

Abstract

The results of a search for solar axions from the Korea Invisible Mass Search (KIMS) experiment at the Yangyang Underground Laboratory are presented. Low-energy electron-recoil events would be produced by conversion of solar axions into electrons via the axio-electric effect in CsI(Tl) crystals. Using data from an exposure of 34,596 $\mathrm{kg}\cdot \mathrm{days}$, we set a 90 \% confidence level upper limit on the axion-electron coupling, $g_{ae}$, of $1.39\times 10^{-11}$ for an axion mass less than 1 keV/${\mathrm{c}}^2$. This limit is lower than the indirect solar neutrino bound, and fully excludes QCD axions heavier than 0.48 eV/${\mathrm{c}}^2$ and 140.9 eV/${\mathrm{c}}^2$ for the DFSZ and KSVZ models respectively.

9 pages, 6 figures