Strange Quark Contribution to the Proton Spin, from Elastic $/vecep$ and $nu p$ Scattering

摘要

The strangeness contribution to the vector and axial form factors of the proton is presented for momentum transfers in the range 0.45 < Q2 < 1.0 GeV2. The results are obtained via a combined analysis of forward-scattering parity-violating elastic (approximately) ep asymmetry data from the G0 and HAPPEx experiments at Jefferson Lab, and elastic n p and n p scattering data from Experiment 734 at Brookhaven National Laboratory. The combination of the two data sets allows for the simultaneous extraction of Gs E, Gs M, and Gs A over a significant range of Q2 for the very first time. Determination of the strange axial form factor Gs A is vital to an understanding of the strange quark contribution to the proton spin.