C.E. Jones

Parity-Violating Electron Deuteron Scattering and the Proton's Neutral Weak Axial Vector Form Factor

We report on a new measurement of the parity-violating asymmetry in quasielastic electron scattering from the deuteron at backward angles at Q2=0.038 (GeV/c)2. This quantity provides a determination of the neutral weak axial vector form factor of the nucleon, which can potentially receive large electroweak corrections. The measured asymmetry A=-3.51+/-0.57 (stat)+/-0.58 (syst) ppm is consistent with theoretical predictions. We also report on updated results of the previous experiment at Q2=0.091 (GeV/c)2, which are also consistent with theoretical predictions.

A liquid hydrogen target for the precision measurement of the weak mixing angle in Møller scattering at SLAC

A 150 cm long liquid hydrogen target has been built for the SLAC End Station A E158 experiment. The target loop volume is 55 liters, and the maximum target heat load deposited by the electron beam is {approx} 700 W. The liquid hydrogen density fluctuation with full beam current (120 Hz repetition rate, 6 x 10{sup 11} electrons/spill) on target is well below 10{sup -4} level, which fulfills the requirement for a precision measurement of the weak mixing angle in the polarized electron-electron scattering process.

Two body photodisintegration of the deuteron up to 2.8 GeV

Measurements were performed for the photodisintegration cross section of the deuteron for photon energies from 1.6 GeV to 2.8 GeV and center‐of‐mass angles from 37° to 90°. The measured cross section at θcm=90° are in agreement with the constituent counting rules.

Proton propagation through nuclei and the quasi-free reaction mechanism studied with (e,e′p)reactions

Jefferson Lab experiment E91-013 measured the energy dependence of proton propagation in nuclei, using the quasi-free (e, e{prime}p) reaction. The ratios of the experimental (e, e{prime}p) cross-sections integrated over the quasi-free region to PWIA calculations are presented as a function of momentum transfer, (0.6 < Q{sup 2} < 3.3 GeV{sup 2}) and target nucleus (C, Fe and Au). As a first step towards a longitudinal and transverse separation of the quasi-free cross-section, a super ratio of the measured to the calculated cross-sections at forward and backward angles is presented.

Measurement of pzzof the laser‐driven polarized deuterium target

The question of whether nuclei are polarized as a result of H–H(D–D) spin‐exchange collisions within the relatively dense gas of a laser‐driven source of polarized hydrogen (deuterium) can be addressed directly by measuring the nuclear polarization of atoms from the source. The feasibility of using a polarimeter based on the D+T→n+4He reaction to measure the tensor polarization of deuterium in an internal target fed by the laser‐driven source has been tested. The device and the measurements necessary to test the spin‐exchange polarization theory are described.

Measurement of [ital p][sub [ital zz]] of the laser-driven polarized deuterium target

The question of whether nuclei are polarized as a result of H–H(D–D) spin‐exchange collisions within the relatively dense gas of a laser‐driven source of polarized hydrogen (deuterium) can be addressed directly by measuring the nuclear polarization of atoms from the source. The feasibility of using a polarimeter based on the D+T→n+4He reaction to measure the tensor polarization of deuterium in an internal target fed by the laser‐driven source has been tested. The device and the measurements necessary to test the spin‐exchange polarization theory are described.