Study of electron-neutrino--electron elastic scattering at LAMPF

Neutrino-electron elastic scattering was observed with a 15-ton fine-grained tracking calorimeter exposed to electron neutrinos from muon decay at rest. The measured [nu][sub [ital e]e][sup [minus]][r arrow][nu][sub [ital e]e][sup [minus]] elastic scattering rate of 236[plus minus]35 events yields the total elastic scattering cross section 10.0[plus minus]1.5(stat)[plus minus]0.9(syst)[times]10[sup [minus]45] cm[sup 2][times][[ital E][sub [nu]] (MeV)], and a model-independent measurement of the strength of the destructive interference between the charged and neutral currents, [ital I]=[minus]1.07[plus minus]0.21, that agrees well with the standard model (SM) prediction [ital I]=[minus]1.08. The agreement between the measured electroweak parameters and SM expectations is used to place limits on neutrino properties, such as neutrino flavor-changing neutral currents and neutrino electromagnetic moments. Limits are placed on the masses of new bosons that interact with leptons: for a neutral tensor boson, [ital M][sub [ital T]][gt]105 GeV; for a neutral (pseudo)scalar boson, [ital M][sub [ital P],][ital S][gt]47 GeV; for a charged Higgs boson, [ital M][sub [chi]][sup +][gt]87 GeV; and for a purely left-handed charged (neutral) vector boson, [ital M][sub [ital x]][gt]239 (119) GeV.