Two-Neutrino Five-Photon Scattering at Low Energies

Abstract

We extend earlier constructions of the effective action for neutrino-photon scattering, using the connection between low-energy neutrino-photon and photon-photon scattering together with the known effective Lagrangian describing low-energy photon scattering in QED. We use this effective action to calculate analytic expressions for the low-energy cross section for the (unpolarised) processes $\nu \text{nubar}\to 5\gamma$, $\nu \gamma \to \nu +4\gamma$ and $\gamma \gamma \to \nu \text{nubar}+3\gamma$. As a byproduct we derive compact expressions for the $N$-body phase-space integrals for massless particles, including those having non-trivial tensor-structure.

Comments: 14 pages, plain tex, no figures. Two references added