Effect of the 3K background radiation on ultrahigh energy cosmic rays

Abstract

In this work we re-examine the opacity of the cosmic background radiation to the propagation of extremely high energy cosmic rays. We use the continuous energy loss approximation to provide spectral modification factors for several hypothesized cosmic ray sources. Earlier problems with this approximation are resolved including the effects of resonances other than the $\Delta$.

Comments: 13 pages revtex, 3 figures. To appear in Phys. Rev. D