Neutrino magnetic moments and photo-disintegration of deuterium

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 7Be(p,γ)8B reaction which give a more precise value of the solar 8B flux we find that the neutrino effective magnetic moment is μeff2=(-2.76±1.46)x10-16μB2 which can be interpreted as an upper bound vertical bar μeffvertical bar <3.71x10-9μB (at 95% C.L.) on the neutrino magnetic moments