Axion-electron coupling from the RGB tip of Globular Clusters

Abstract

We present a preliminary study of the Globular Cluster RGB devoted to improve the available constraint for the axion-electron coupling. By means of multi-band IR photometry of the cluster M3 we obtain g_{ae}/10^{-13} < 2.57 (95\% C.L.).

paper submitted to Proceedings of the 13th Patras Workshop on Axions, WIMPs and WISPs (Patras2017)"