Strange form factors of the proton: a new analysis of the v ((v)over-bar) data of the BNL-734 experiment

We consider ratios of elastic nu(<(nu)over bar>)-proton cross sections meas ured by the Brookhaven BNL-734 experiment and use them to obtain the neutra l current (NC) over charged current (CC) neutrino-antineutrino asymmetry. W e discuss the sensitivity of these ratios and of the asymmetry to the elect ric, magnetic and axial strange form factors of the nucleon and to the axia l cutoff mass M-A. We show that the effects of the nuclear structure and in teractions on the asymmetry and, in general, on ratios of cross sections ar e negligible. We find some restrictions on the possible values of the param eters characterizing the strange form factors. We show that a precise measu rement of the neutrino-antineutrino asymmetry would allow the extraction of the axial and vector magnetic strange form factors in a model independent way. The neutrino-antineutrino asymmetry turns out to be almost independent on the electric strange form factor and on the axial cutoff mass. (C) 1999 Elsevier Science B.V. All rights reserved.