Standard physics is capable to interpret $\sim$18 TeV photons from GRB 221009A

It is reported that the Large High Altitude Air Shower Observatory (LHAASO) observed thousands of very-high-energy photons up to $\sim$18 TeV from GRB 221009A. We study the survival rate of these photons by considering the fact that they are absorbed by the extragalactic background light. By performing a set of $10^6$ Monte-Carlo simulations, we explore the parameter space allowed by current observations and find that the probability of predicting that LHAASO observes at least one photons of $\sim$18 TeV from GRB 221009A within 2000 seconds is 80\% and 25\% if assuming the spectral index of photon flux is $-2$ and $-3$, respectively. Hence, it is still possible for the standard physics to interpret the observation of LHAASO in the energy range of several TeV. Our research method can be straightforwardly generalized to study more data sets of LHAASO and other experiments in the future.Comment: 5 pages, 2 figure