Electroweak observables in neutrino-electron scattering from a muon storage ring

Abstract

We investigate the sensitivity of a companion neutrino detector situated in the plane of a high-energy, high-intensity muon storage ring to elastic ν μ and ν e scattering on electrons (EνES). Assuming a muon collider with center-of-mass energies of up to 10 TeV, we report sensitivity to the weak couplings g V and g A up to around 0.05% relative error, and sensitivity to the weak mixing angle in the momentum transfer Q ∈ [10 −2 , 2] GeV range up to around 0.03% relative error. EνES measurements with high-energy muon storage rings allow one to directly interrogate the momentum-transfer regime associated with the NuTeV anomaly. This level of precision allows unique sensitivity to the momentum-dependence of sin 2 θ W . We estimate that with the neutrinos from a E μ = 1.5 TeV (or higher) muon collider, the hypothesis that sin 2 θ W does not “run” can be safely ruled out.