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The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved

The cross section for the elastic scattering reaction νe + e − → νe + e − was measured by the Liquid Scintillator Neutrino Detector using a µ + decay-at-rest νe beam at the Los Alamos Neutron Science Center. The standard model of electroweak physics predicts a large destructive interference between the charge current and neutral current channels for this reaction. The measured cross section, σ νee − = [10.1 ± 1.1(stat.) ± 1.0(syst.)] × Eν e (MeV) ×10 −45 cm 2 , agrees well with standard model expectations. The measured value of the interference parameter, I = −1.01 ± 0.13(stat.) ± 0.12(syst.), is in good agreement with the standard model expectation of I SM = −1.09. Limits are placed on neutrino flavorchanging neutral currents. An upper limit on the muon-neutrino magnetic moment of 6.8 × 10 −10 µ Bohr is obtained using the νµ andνµ fluxes from π + and µ + decay.

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We present data on the inclusive scattering of polarized electrons from a polarized 3He target at energies from 0.862 to 5.06 GeV, obtained at a scattering angle of 15.5 degrees. Our data include measurements from the quasielastic peak, through the nucleon resonance region, and beyond, and were used to determine the virtual photon cross-section difference sigma(1/2)-sigma(3/2). We extract the extended Gerasimov-Drell-Hearn integral for the neutron in the range of four-momentum transfer squared Q2 of 0.1-0.9 GeV2.