A potential test of the CP properties and Majorana nature of neutrinos

The cross section of the scattering of solar neutrinos on electrons is sensitive to the neutrino dipole moments through an interference of electromagnetic and weak amplitudes. We show how future solar neutrino experiments with good angular resolution and low energy threshold, such as Hellaz, can be sensitive to the resulting azimuthal asymmetries in event number, and could therefore provide valuable information on the CP properties and the nature of the neutrinos, provided the solar magnetic field direction is fixed