Constraining neutrino lifetimes and magnetic moments via solar neutrinos in the large xenon detectors

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) greater than or similar to 3 x 10(-2) s/eV and tau(2) /m(2) greater than or similar to 8 x 10(-3) s/eV at the 2 sigma level can be obtained for a total exposure of 70 ton . year. Furthermore, a restrictive constraint on the effective magnetic moment of neutrinos mu(eff) less than or similar to 2.6 x 10(-12) mu(B), with mu(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.