Neutrino magnetic moments and low-energy solar neutrino-electron scattering experiments

The scattering of solar neutrinos on electrons is sensitive to the neutrino magnetic moments through an interference of electromagnetic and weak amplitudes in the cross section. We show that future low-energy solar neutrino experiments with good angular resolution can be sensitive to the resulting azimuthal asymmetries in event number and should provide useful information on non-standard neutrino properties such as magnetic moments. We compare asymmetries expected at Hellaz (mainly $\mathrm{pp}$ neutrinos) with those at the Kamiokande and Super-Kamiokande experiments (boron neutrinos), both for the case of Dirac and Majorana neutrinos and discuss the advantages of low energy experiments. Potentially interesting information on the solar magnetic fields may be accessible.