Constraining Neutrino Lifetimes and Magnetic Moments via Solar Neutrinos in the Large Xenon Detectors

TL;DR

This paper demonstrates that large liquid xenon detectors can significantly improve constraints on neutrino lifetimes and magnetic moments through precise solar neutrino measurements, surpassing current laboratory limits.

Contribution

It provides new projected limits on neutrino lifetimes and magnetic moments using solar neutrino data from large xenon detectors, considering different decay scenarios and neutrino mass spectra.

Findings

Lower bounds on neutrino lifetimes: τ₁/m₁ ≳ 3×10⁻² s/eV and τ₂/m₂ ≳ 8×10⁻³ s/eV.

Constraint on neutrino magnetic moment: μ_eff ≲ 2.6×10⁻¹² μ_B.

Improved limits are achievable with 70 ton·year exposure.

Abstract

The multi-ton-scale liquid xenon detectors, with an excellent energy resolution of a few keV, will be constructed to probe the dark-matter particles. In this paper, we show that precision measurements of the low-energy solar neutrinos via the elastic neutrino-electron scattering in this kind of detectors are able to improve the present limits on neutrino lifetimes and neutrino magnetic moments by about one order of magnitude. We carefully study the impact of the unknown neutrino mass spectrum on the ultimate limits in the case of non-radiative visible neutrino decays. In the case of invisible neutrino decays, the lower bounds $\tau^{}_1/m^{}_1 \gtrsim 3 \times 10^{-2}~{\rm s}/{\rm eV}$ and $\tau^{}_2/m^{}_2 \gtrsim 8\times 10^{-3}~{\rm s}/{\rm eV}$ at the $2\sigma$ level can be obtained for a total exposure of $70~{\rm ton}\cdot {\rm year}$. Furthermore, a restrictive constraint on the effective magnetic moment of neutrinos $\mu^{}_{\rm eff} \lesssim 2.6\times 10^{-12}~\mu^{}_{\rm B}$, with $\mu^{}_{\rm B}$ being the Bohr magneton, can be achieved. This is among the best results that will be available in the laboratory experiments in the near future.