Standard physics is still capable to interpret ～18 TeV photons from GRB 221009A

Abstract: It is reported that the Large High Altitude Air Shower Observatory (LHAASO) observed thousands 9 of very-high-energy photons up to ∼18 TeV from GRB 221009A. We study the survival rate of these 10 photons by considering the fact that they are absorbed by the extragalactic background light. By performing a set of 10 11 6 Monte-Carlo simulations, we explore the parameter space allowed by current 12 observations and find that the probability of predicting that LHAASO observes at least one photons 13 of 18 TeV from GRB 221009A within 2000 seconds is 4–5%. Hence, it is still possible for the standard 14 physics to interpret LHAASO’s observation in the energy range of several TeV. Our method can be 15 straightforwardly generalized to study more data sets of LHAASO and other experiments in the future.