Neutrino magnetic moments and photo-disintegration of deuterium

Abstract

Neutrinos with non-zero magnetic moments can dissociate deuterium nuclei by a photon exchange, in addition to the weak neutral current process. We calculate the neutrino-magnetic moment induced photo-dissociation cross section of deuterium using the equivalent photon method. This process would contribute extra events to the neutral current reaction which is observed with high precision in the salt-phase of SNO experiment. Using the SNO data and the recent laboratory measurements of the ${}^{7}Be(p,\gamma {)}^{8}B$ reaction which give a more precise value of the solar ${}^{8}B$ flux we find that the neutrino effective magnetic moment is ${\mu }_{eff}^2=(-2.76\pm 1.46)\times 10^{-16}{\mu }_B^2$ which can be interpreted as an upper bound $|{\mu }_{eff}|<3.71\times 10^{-9}{\mu }_B$ (at $95$) on the neutrino magnetic moments.

7 pages, new references and some comments added