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

The scattering of solar neutrinos on electrons may reveal their CP properti es, which are particularly sensitive to their Majorana nature. The cross se ction is sensitive to the neutrino dipole moments through an interference o f electromagnetic and weak amplitudes. We show how future solar neutrino ex periments with good angular resolution and low energy threshold, such as He llaz, can be sensitive to the resulting azimuthal asymmetries in event numb er, and could therefore provide valuable information on the CP properties a nd the nature of the neutrinos, provided the solar magnetic field direction is fixed. (C) 2000 Elsevier Science B.V. All rights reserved.