Experiment GEMMA: Search for the Neutrino Magnetic Moment

Abstract

The result of the 3-year neutrino magnetic moment measurement at the Kalinin Nuclear Power Plant (KNPP) with the GEMMA spectrometer is presented. Antineutrino-electron scattering is investigated. A high-purity germanium detector of 1.5 kg placed at a distance of 13.9 m from the centre of the 3 GW th reactor core is used in the spectrometer. The antineutrino flux is 2.7×10 13ν e /cm 2 /s. The differential method is used to extract ν-e electromagnetic scattering events. The scattered electron spectra taken in 5184+6798 and 1853+1021 hours for the reactor ON and OFF periods are compared. The upper limit for the neutrino magnetic moment µ ν was found to be 3.2×10 −11 µ B at 90% CL.