On parton distributions in a photon gas

Abstract

In some cases it may be useful to know parton distributions in a photon gas. This may be relevant, e.g., for the analysis of interactions of high energy cosmic ray particles with the cosmic microwave background radiation. The latter can be considered as a gas of photons with an almost perfect blackbody spectrum. An approach to finding such parton distributions is described. The survival probability of ultra-high energy neutrinos traveling through this radiation is calculated.Comment: 5 pages, 4 figures, EPJ style files. Some changes in the text. Two new sections discussing ultra-high energy neutrino damping in the cosmic microwave background radiation are include