The strongest bound on axion-photon coupling from globular clusters
by
Adrian Ayala(Física teórica y del cosmos department, Granada University)
→
Europe/Berlin
Building 67, SemRm 10 (DESY Hamburg)
Building 67, SemRm 10
DESY Hamburg
Description
Stellar evolutionary arguments provide a tool to constrain properties of “new physics” particles, e.g. axion and axion-like particles (ALP). In this talk we will discuss why stars are good laboratories to test axion/ALP-photon coupling, gag. Strongest upper bound of gag < 0.66 × 10^(-10) (95% confidence level) is found by comparing measurements of galactic globular cluster (GGC) R parameter (ratio of stars in HB over upper RGB branch) with simulations. The importance of accurate knowledge of initial helium mass fraction (Y) of the GGC, in order to obtain reliable gaγ bounds is pointed out. Work in progress to take under control uncertainties affecting our simulations will be reviewed too.
