Two-neutrino five-photon scattering at low energies - art. no. 113006

We extend earlier constructions of the effective action for neutrino-photon scattering, using the connection between low-energy neutrino-photon and ph oton-photon scattering together with the known effective Lagrangian describ ing low-energy photon scattering in QED. We use this effective action to ca lculate analytic expressions for the low-energy cross section for the (unpo larized) processes nu<(<nu>)over bar>-->5 gamma, nu gamma --> nu+ 4 gamma, and gamma gamma --> nu<(<nu>)over bar> +3 gamma. As a byproduct we derive c ompact expressions for the N-body phase-space integrals for massless partic les, including those having nontrivial tensor structure.