Direct computation of inelastic photon-neutrino processes in the Standard Model

In this paper, we compute the Standard Model polarized amplitudes and cross sections of the processes gamma v --> gamma gamma v, gamma gamma --> gamma v (v) over bar and v (v) over bar --> gamma gamma gamma, for centre-of-mas s energies omega within the range of validity of the Fermi theory. By using a large electron-mass expansion of the exact result, we also derive the fi rst correction term to the effective, low-energy ( < m(e)) formula for gamm a v --> gamma gamma v. Finally, we discuss possible astrophysical implicati ons of our results and provide simple fits to the exact expressions. (C) 19 99 Elsevier Science B.V.