Speaker
Description
We investigate the potential of core-collapse supernovae (SNe) to constrain axion-like particles (ALPs) coupled to nucleons and electrons. ALPs coupled to nucleons can be efficiently produced in the SN core via nucleon-nucleon bremsstrahlung and, for a wide range of parameters, leave the SN unhindered producing a large ALP flux. For masses exceeding 1 MeV, these ALPs would decay into electron-positron pairs, generating a positron flux. In the case of Galactic SNe, the annihilation of the created positrons with the electrons present in the Galaxy would contribute to the 511 keV annihilation line. Using the SPI (SPectrometer on INTEGRAL) observation of this X-ray line, allows to exclude a wide range of the axion-electron coupling $10^{-19} < g_{ae} < 10^{-11}$ for $g_{ap} \sim 10^{-9}$. If ALPs decay in the extra-galactic medium, the electron-positron annihilations would yield a contribution to the cosmic X-ray background, allowing couplings down to $g_{ae}\sim 10^{-20}$ to be constrained.
