gamma nu -> gamma gamma nu and crossed processes at energies below m_W

Abstract

The cross sections for the processes $\gamma \nu \to \gamma \gamma \nu$, $\gamma \gamma \to \gamma \nu \bar{\nu }$ and $\nu \bar{\nu }\to \gamma \gamma \gamma$ are calculated for a range of center of mass energies from below $m_e$ to considerably above $m_e$, but much less than $m_W$. This enables us to treat the neutrino--electron coupling as a four--Fermi interaction and results in amplitudes which are electron box diagrams with three real photons and one virtual photon at their vertices. These calculations extend our previous low--energy effective interaction results to higher energies and enable us to determine where the effective theory is reliable.

Comments: 12 pages, RevTex, 10 postscript figures included