Investigating the gamma-ray burst from decaying MeV-scale axion-like particles produced in supernova explosions

Abstract We investigate the characteristics of gamma-ray signal following decay MeV-scale Axion-Like Particles (ALPs) coupled to photons which are produced in a Supernova (SN) explosion. This analysis is first include production heavier ALPs through photon coalescence process, enlarging mass range that could be observed this way and giving stronger bound from observation SN 1987A. Furthermore, we present new analytical method for calculating predicted ALP decays. With can rigorously prove validity an approximation has been used some previous literature, show here valid only if all gamma rays arrive under extremely small angles (i.e. very close line sight SN). However, it also shows where not valid, offers efficient alternative calculate ALP-induced flux general setting when guaranteed small. estimate sensitivity Fermi Large Area Telescope ( -LAT) future nearby case non-observation current bounds on ALP-photon coupling g aγ strengthened by about order magnitude. In observation, may possible reconstruct product 2 m , with ALP.