GEMMA experiment: three years of the search for the neutrino magnetic moment

TL;DR

This paper reports a three-year experimental search for the neutrino magnetic moment using a high-purity germanium detector near a nuclear reactor, setting an upper limit of < 3.2E-11 Bohr magnetons at 90% CL.

Contribution

It presents the first three-year measurement of the neutrino magnetic moment with a high-purity germanium detector at a nuclear reactor, improving experimental constraints.

Findings

Upper limit for neutrino magnetic moment < 3.2E-11 Bohr magnetons at 90% CL

Compared electron spectra during reactor ON and OFF periods

Used differential scattering method to analyze data

Abstract

The result of the 3-year neutrino magnetic moment measurement at the Kalinin Nuclear Power Plant 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 2.7E13 1/scm/s. The differential method is used to extract (nu-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 < 3.2E-11 Bohr magneton at 90% CL is derived from the data processing.