The strange quark contribution to the proton's magnetic moment

We report a news determination of the strange quark contribution to the proton's magnetic form factor at a four-momentum transfer Q(2) = 0.1 (GeV/c)(2) from parity-violating e-p elastic scattering. The result uses a revised analysis of data from the SAMPLE experiment which was carried out at the MIT-Bates Laboratory. The data are combined with a calculation of the proton's axial form factor-G(A)(e) to determine the strange form factor G(M)(s) (Q(2) = 0.1) = 0.37 +/- 0.20 +/- 0.26 +/- 0.07. The extrapolation of G(M)(s) to its Q(2) = 0 limit and comparison with calculations is also discussed. (C) 2004 Published by Elsevier B.V.