V. Zeps

Transverse beam spin asymmetries in forward-angle elastic electron-proton scattering

We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely polarized 3 GeV electrons from unpolarized protons at Q2=0.15, 0.25 (GeV/c)2. The results are inconsistent with calculations solely using the elastic nucleon intermediate state and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A(n) provides a direct probe of the imaginary component of the 2gamma exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.

The TJNAF Hall A Möller polarimeter

As part of the spin physics program at Jefferson Lab, a Moller polarimeter is being developed to measure the polarization of electron beams of energies 0.8 to 6 GeV. The device uses electron-electron scattering in a set-up in which the polarized beam is scattered from a polarized electron target. A unique signature for Moller scattering is obtained using a series of three quadrupole magnets which provide angular selection, and a dipole magnet for energy analysis. Here, the design and commissioning of this polarimeter will be discussed along with future plans to use its small scattering angle capabilities to investigate physics in the very low q2 regime.