The SAMPLE experiment: Parity-violating electron scattering from the proton and deuteron

Recent experimental evidence on nucleon structure has provided indications that some strange quark matrix elements can be comparable to those involving up and down quarks. The SAMPLE experiment will determine the strange magnetic form factor GsM at Q2=0.1 (GeV/c)2 from a measurement of the asymmetry in the scattering of polarized electrons from the proton. The error on the extraction of GsM is ultimately limited by a theoretical uncertainty—the uncertain electroweak hadronic radiative correction to the axial form factor, RT=1A. To address this issue, the collaboration is also approved to measure the asymmetry in parity‐violating quasielastic electron scattering from the deuteron. The combination of the proton and deuteron measurements will yield a value of GsM that is almost completely free of the uncertainty in RT=1A.