DYNAMICAL ZEROS IN NEUTRINO-ELECTRON ELASTIC-SCATTERING AT LEADING ORDER

We show the existence of dynamical zeros in the helicity amplitudes fo r neutrino-electron elastic scattering at lowest order in the standard theory. In particular, the lambda=1/2 nonflip electron helicity ampli tude in the electron-antineutrino process vanishes for an incident neu trino energy E(v)=m(e)/(4 sin(2) theta(W)) and forward electrons (maxi mum recoil energy). The rest of the helicity amplitudes show kinematic al zeros in this configuration and therefore the cross section vanishe s. Prospects to search for the neutrino magnetic moment are discussed.