Limit On the Neutrino Magnetic Moment Using 1496 Days of Super-Kamiokande-i Solar Neutrino Data

TL;DR

This study used 1496 days of Super-Kamiokande-I data to search for a neutrino magnetic moment, setting upper limits that improve previous constraints by incorporating neutrino oscillation effects and additional experimental data.

Contribution

It provides the most stringent upper limits on the neutrino magnetic moment using solar neutrino data, accounting for neutrino oscillations and combining multiple experimental results.

Findings

Upper limit of $oldsymbol{3.6 imes 10^{-10}}$ $oldsymbol{\mu_B}$ at 90% C.L. from Super-Kamiokande data.

Stronger limit of $oldsymbol{1.1 imes 10^{-10}}$ $oldsymbol{\mu_B}$ at 90% C.L. when combining with other experiments.

No evidence of a non-zero neutrino magnetic moment was observed.

Abstract

A search for a non-zero neutrino magnetic moment has been conducted using 1496 live days of solar neutrino data from {\SK}. Specifically, we searched for distortions to the energy spectrum of recoil electrons arising from magnetic scattering due to a non-zero neutrino magnetic moment. In the absence of clear signal, we found $\mu_{\nu} \leq 3.6 \times 10^{-10}$ $\mu_{B}$ at 90% C.L. by fitting to the Super-Kamiokande day/night spectra. The fitting took into account the effect of neutrino oscillation on the shapes of energy spectra. With additional information from other solar neutrino and KamLAND experiments constraining the oscillation region, a limit of $\mu_{\nu} \leq 1.1 \times 10^{-10}$ $\mu_{B}$ at 90% C.L. was obtained.