Low energy analysis of νN → νNγ in the standard model

The production of single photons in low energy (similar to 1 GeV) neutrino scattering off nucleons is analyzed in the standard model. At very low energies, E-nu << GeV, a simple description of the chiral Lagrangian involving baryons and arbitrary SU(2)(L) x U(1)(Y) gauge fields is developed. Extrapolation of the process into the similar to 1-2 GeV region is treated in a simple phenomenological model. Coherent enhancements in compound nuclei are studied. The relevance of single-photon events as a background to experimental searches for nu(mu) -> nu(e) is discussed. In particular, single photons are a plausible explanation for excess events observed by the MiniBooNE experiment.