Potential measurement of the weak mixing angle with neutrino-electron scattering at low energy

Abstract: We study the possibility to measure sin² theta_W by neutrino-electron scattering at a value of the momentum transfer Q ~ 30 MeV with a precision of 0.24% which is only a factor three below the one obtained by LEP-I at the Z-pole. The neutrino source is a proton beam dump providing a clean beam from muon decay at rest and the detector is a 100 kt scale water Cerenkov detector, which results in about 20 million signal events.