Photon emission in neutral current interactions with nucleons and nuclei.

We report on our study of photon emission induced by Eν ~ 1 GeV (anti)neutrino neutral current interactions with nucleons and nuclei. This process is an important background for νe appearance oscillation experiments. At the relevant energies, the reaction is dominated by the excitation of the Δ(1232) resonance but there are also non-resonant contributions that, close to threshold, are fully determined by the effective chiral Lagrangian of strong interactions. We have obtained differential and integrated cross section for the (anti)neutrino-nucleon scattering and compare them with previous results. Furthermore, we have extended the model to nuclear targets taking into account Fermi motion, Pauli blocking and the in-medium modifications of the Δ properties. This study is important in order to reduce systematic effects in neutrino oscillation experiments. [ABSTRACT FROM AUTHOR]