Measurement of interference between<i>W</i>and<i>Z</i>exchange in electron-neutrino electron scattering

Abstract

A measurement of the reaction ${\ensuremath{\nu}}_{\mathit{e}}$+${\mathit{e}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${\ensuremath{\nu}}_{\mathit{e}}$+${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ was performed using a beam-stop source of ${\ensuremath{\nu}}_{\mathit{e}}$. Based upon 234\ifmmode\pm\else\textpm\fi{}35 events, we obtain a cross section of \ensuremath{\sigma}(${\ensuremath{\nu}}_{\mathit{e}}$e)=[9.9\ifmmode\pm\else\textpm\fi{}1.5(stat)\ifmmode\pm\else\textpm\fi{}1.0(syst)]\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}42}$ ${\mathrm{cm}}^{2}$ \ifmmode\times\else\texttimes\fi{}[${\mathit{E}}_{\ensuremath{\nu}}$ (GeV)]. This reaction is mediated by the exchange of W and Z bosons and is thus sensitive to the interference between them. This interference is measured to be -1.07\ifmmode\pm\else\textpm\fi{}0.17(stat)\ifmmode\pm\else\textpm\fi{}0.11(syst), consistent with the destructive interference (-1.08) predicted by the standard model.