Measurement of electron-neutrino electron elastic scattering

The cross section for the elastic scattering reaction ${\nu }_e{+e}^{-}\to {\nu }_e{+e}^{-}$ was measured by the Liquid Scintillator Neutrino Detector using a ${\mu }^{+}$ decay-at-rest ${\nu }_e$ beam at the Los Alamos Neutron Science Center. The standard model of electroweak physics predicts a large destructive interference between the charge current and neutral current channels for this reaction. The measured cross section, ${\sigma }_{{\nu }_e{e}^{-}}=[10.1\pm 1.1(\mathrm{stat})\pm 1.0(\mathrm{syst}\left)\right]\times E_{{\nu }_e}\left(\mathrm{MeV}\right)\times {10}^{-45}{\mathrm{cm}}^2,$ agrees well with standard model expectations. The measured value of the interference parameter, $I=-1.01\pm 0.13\left(\mathrm{stat}\right)\pm 0.12\left(\mathrm{syst}\right),$ is in good agreement with the standard model expectation of $I^{\mathrm{SM}}=-\mathrm{1.09.}$ Limits are placed on neutrino flavor-changing neutral currents. An upper limit on the muon-neutrino magnetic moment of $6.8\times {10}^{-10}{\mu }_{\mathrm{Bohr}}$ is obtained using the ${\nu }_{\mu }$ and ${\overline{\nu }}_{\mu }$ fluxes from ${\pi }^{+}$ and ${\mu }^{+}$ decay.