NEUTRINO MAGNETIC-MOMENT UPPER BOUND FROM SOLAR-NEUTRINO OBSERVATIONS

Using the data from SuperKamiokande, Kamiokande, and Homestake solar n eutrino experiments we derive an upper bound on the magnetic moment of the neutrino and find mu(upsilon e) less than or equal to (2.2-2.3) x 10(-10)mu(B), within four different standard solar models. We assume equal magnetic moments for all neutrino flavors. This limit is obtaine d when neutrinos do not undergo any ''disappearance'' mechanism other than the magnetic moment conversion due to the solar magnetic field an d for a total or nearly total suppression of the intermediate energy n eutrinos. In our work we consider an energy-dependent suppression of s olar neutrinos. We also point out that the limit may be further reduce d if the detector threshold energy in upsilon(e,x)e(-) scattering with solar neutrinos is decreased.