Axion-like particles explain the very-high energy emission from GRB221009A

Giorgio Galanti, Marco Roncadelli, Fabrizio Tavecchio

Published 2022-10-11Version 1

We show that the very recent detection of the gamma ray burst GRB221009A by the LHAASO experiment -- with its very-high-energy tail extending up to 18 TeV -- provides a hint at the existence of axion-like-particles with mass ${\cal O} (10^{-10}) \, {\rm eV}$ and two-photon coupling ${\cal O} (10^{-11}) \, {\rm GeV}^{- 1}$.