Inelastic photon-neutrino interactions using an effective Lagrangian - art. no. 013008

We justify the feasibility of substituting a photon leg by a neutrino curre nt in the Euler-Heisenberg Lagrangian to obtain an effective Lagrangian for the process gamma upsilon --> gamma gamma upsilon and its crossed reaction s. We establish the link between these professes and the four-photon scatte ring in both the standard model and the effective theory. As an application , we compute the processes gamma upsilon --> gamma gamma upsilon and gamma gamma --> gamma upsilon<(upsilon)over bar>, give their polarized cross sect ions, and show how to use the gamma gamma --> gamma gamma results as a chec k. We settle the question about the disagreement between two computations i n the literature concerning the reaction gamma gamma --> gamma upsilon<(ups ilon)over bar>.