http://arxiv.org/abs/2210.07172
The nearby GRB22109A at redshift $z=0.1505$ has been observed up to a maximum energy of 18 TeV with the LHAASO air shower array. The expected optical depth for a photon with energy $E_\gamma=18$~TeV varies between 9.2 and 27.1 according to existing models of the extra-galactic background light in the relevant mid infra-red range. The resulting suppression of the flux makes it unlikely that this photon could be observed. If the photon event and its energy are however confirmed and possibly even more photons above 10 TeV have been observed, the photon-pairproduction process would have to be suppressed by mechanisms predicted in extensions of the standard model of particle physics. We consider the possibilities of photon mixing with a light pseudo-scalar (e.g., axion-like particle: ALP) in the magnetic field of the host galaxy and the Milky Way and Lorentz-invariance violation (LIV). In the case of photon-ALP mixing, the boost factor would reach values $\sim10^6$ for photon couplings not ruled out by the CAST experiment. In the case of LIV, required boost factors are achievable for a LIV breaking energy scale $\lesssim 10^{28}$ eV for the linear modification of the dispersion relation and $\lesssim 10^{20}$ eV for the quadratic modification. A more simple explanation would be a misidentification of a charged cosmic-ray air shower.
A. Baktash, D. Horns and M. Meyer
Fri, 14 Oct 22
18/75
Comments: N/A
You must be logged in to post a comment.