Photon emission in neutral current interactions at intermediate energies

Understand

Neutral current photon emission reactions with nucleons and nuclei are studied.

• These processes are important backgrounds for nu_mu to nu_e (bar(nu)_mu to bar(nu)_e) appearance oscillation experiments where electromagnetic showers instigated by electrons (positrons) and photons are not distinguishable.
• At intermediate energies, these reactions are dominated by the weak excitation of the Delta(1232) resonance and its subsequent decay into Ngamma There are also non-resonant contributions that, close to threshold, are fully determined by the effective chiral Lagrangian of strong interactions.
• In addition, we have also included mechanisms mediated by nucleon excitations (N*) from the second resonance region above the Delta(1232).