Speaker
Description
MeV scale axion-like particles can be produced with semi-relativistic velocities in Galactic supernovae, leading to a diffuse flux that can be detectable in neutrino water-Cherenkov detectors. This is possible through their absorption on free protons, ap→pγ, where the resulting photon has approximately the energy of the ALP. This new signature is complementary to the usual one from oxygen de-excitation, and can be exploited in various ways. Using SuperKamiokande data, new constraints on the ALP-proton coupling can be derived in regions that cooling bounds cannot probe. Also, this new signature, combined with the one expected at 7 MeV from oxygen de-excitation, could allow us to disentangle ALP-neutron and ALP-proton couplings in the case of a detection.