Search for non-zero neutrino magnetic moments using Super-Kamiokande-I solar neutrino data.

摘要

Non-zero neutrino magnetic moments would mean new physics beyond the standard model. Therefore a search for a nonzero neutrino magnetic moment has been conducted using the high statistic 1496 live day solar neutrino data from Super-Kamiokande-I. The search looked for distortions to the energy spectrum of recoil electrons from nu-e elastic scattering. A nonzero neutrino magnetic moment would cause an increase of event rates at lower energies. In the absence of clear signal, we found munu ≤ 3.6 x 10-10 muB at 90% C.L. by fitting to the Super-Kamiokande (Super-K) day/night energy spectra. The fitting took into account the effect of neutrino oscillations on the shape of energy spectra. With the results from other neutrino experiments constraining the oscillation parameter region, a limit of munu ≤ 1.1 x 10 -10 muB at 90% C.L. was obtained.