NEW RESULTS ON INVERSE MUON DECAY AND LOW MULTIPLICITY REACTIONS

New results on inverse muon decay and coherent charged pion production by neutrinos are presented. The data come from the CHARM-II neutrino detector operated at the CERN wide-band neutrino beam. High-statistics data samples of 14500 inverse muon decay events and 3500 nu(mu)e elas tic scattering events allow the determination of the electroweak param eters from the ratio of the cross-sections of neutral-to-charged-curre nt neutrino electron scattering. The best fit values of the electrowea k mixing angle sin2 theta(W) and the relative coupling strength rho of neutral and charged current are: sin2 theta(W) = 0.237 +/- 0.014 and rho = 0.987 +/- 0.042. In the second topic, coherent single charged pi on production was measured in neutrino and antineutrino beams. The mea sured cross-sections, averaged over the wide-band beam spectra and the glass target nuclei composition, are: sigma(nu(mu)A --> mu-pi+A) = (5 1 +/- 10) X 10(-40) cm2 nucleus and sigma(nu(mu)ABAR --> mu+pi-A) = (4 3 +/- 9) x 10(-40) cm2 nucleus. The energy dependence shows the expect ed flattering of the cross-sections at high energy.