Gemma experiment: Three years of the 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 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 µν <3.2×10 −11 µB at 90% CL is derived from the data processing.

Constraints on dark photon from neutrino-electron scattering experiments

“…There are various neutrino-electron scattering experiments which are mainly TEXONO [13][14][15], BOREXINO [16], GEMMA [17] as well as LSND [18] and CHARM II [19]. A light dark photon could be searched using these data.…”

Testing neutrino magnetic moment in ionization of atoms by neutrino impact

“…Current direct experimental searches [3,4,5] for a magnetic moment of the electron (anti)neutrinos from reactors have lowered the upper limit on µ ν down to µ ν < 3.2 × 10 −11 µ B [5]. These ultra low background experiments use germanium crystal detectors exposed to the neutrino flux from a reactor and search for scattering events by measuring the energy T deposited by the neutrino scattering in the detector.…”

A method for measuring coherent elastic neutrino-nucleus scattering at a far off-axis high-energy neutrino beam target

“…Heavier-mass neutrinos would decay radiatively to lighter-mass neutrinos and emit photons. The best direct experimental limits result for ν − e scattering is from GEMMA experiment, µ ν (ν e ) ≤ 0.32 × 10 −10 µ B [22]. For muon neutrino scattering, the best limit is less stringent: µ ν (ν µ ) ≤ 6.8 × 10 −10 µ B [23].…”