Probe of the hadronic neutral current by final-proton polarization

A systematic phenomenological analysis of the final-proton polarization in the neutral-current reaction ν_μ(ν_μ)p→ν_μ(ν_μ)p is given. It is shown that a measurement of the transverse polarization of the final proton could effectively discriminate between competing gauge-theory models (two classes of models predict large polarizations of opposite sign) and that it could also distinguish V, A neutral-current interactions from S, P, T. Longitudinal and (time-reversal-violating) orthogonal polarizations are also considered, as are the polarizations expected in quasielastic scattering.