Elastic neutrino-electron scattering of solar neutrinos and potential effects of magnetic and electric dipole moments

We consider elastic neutrino-electron scattering of solar neutrinos with ma gnetic moments and electric dipole moments, where the solar neutrino state at the scattering site is determined by the evolution in matter and solar m agnetic fields of the initial electron neutrino state. We present the gener al cross section for an arbitrary superposition of active and sterile neutr ino types with positive and negative helicities, with particular emphasis o n the effect of transverse polarization, which gives rise to an azimuthal a symmetry as a function of the recoil electron momentum. Within our physical ly motivated approximation, we perform a general CP analysis and show that in the 1-Dirac and 2-Majorana neutrino cases no CP-violating effects are pr esent, which means that it is not possible to distinguish between magnetic and electric dipole moments in these cases. We also study the consequences of neutrino energy averaging on the cross section and stress that in the 2- Majorana neutrino case this averaging leads to a suppression of the transve rse neutrino polarization effects. (C) 2000 Elsevier Science B.V. All right s reserved.