Inelastic photon-neutrino interactions using an effective Lagrangian

We justify the feasibility of substituting a photon leg by a neutrino current in the Euler-Heisenberg Lagrangian to obtain an effective Lagrangian for the process γν→γγν and its crossed reactions. We establish the link between these processes and the four-photon scattering in both the standard model and the effective theory. As an application, we compute the processes γν→γγν and γγ→γνν̅ , give their polarized cross sections, and show how to use the γγ→γγ results as a check. We settle the question about the disagreement between two computations in the literature concerning the reaction γγ→γνν̅ .