Neutral-current quark coupling determination using neutrino-neutron and neutrino-proton deep-inelastic cross sections

There is some question about the reliability of inclusive-pion-production analyses as used in previous determinations of the weak neutral-current couplings of u and d quarks. We are able to eliminate this input altogether by using new neutrino and antineutrino data for the ratio of neutral-current neutron-to-proton deep-inelastic cross sections, σ(νn→νX)σ(νp→νX). Another new input to our model-independent analysis is the Q² dependence of elastic neutrino-proton scattering. The final values determined for the neutral-current couplings are consistent with those we obtained previously. For purposes of comparison, we also present a new analysis of high-energy inclusive-pion data.