Transverse Beam Spin Asymmetries at Backward Angles in Elastic Electron-Proton and Quasi-elastic Electron-Deuteron Scattering
Abstract
We have measured the beam-normal single-spin asymmetries in elastic scattering of transversely polarized electrons from the proton, and performed the first measurement in quasi-elastic scattering on the deuteron, at backward angles (lab scattering angle of 108 degrees) for Q2 = 0.22 GeV^2/c^2 and 0.63 GeV^2/c^2 at beam energies of 362 MeV and 687 MeV, respectively. The asymmetry arises due to the imaginary part of the interference of the two-photon exchange amplitude with that of single photon exchange. Results for the proton are consistent with a model calculation which includes inelastic intermediate hadronic (piN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasi-static deuterium approximation, and is also in agreement with theory.
Keywords
Cite
@article{arxiv.1103.3667,
title = {Transverse Beam Spin Asymmetries at Backward Angles in Elastic Electron-Proton and Quasi-elastic Electron-Deuteron Scattering},
author = {The G0 Collaboration and D. Androić and D. S. Armstrong and J. Arvieux and S. L. Bailey and D. H. Beck and E. J. Beise and J. Benesch and F. Benmokhtar and L. Bimbot and J. Birchall and P. Bosted and H. Breuer and C. L. Capuano and Y. -C. Chao and A. Coppens and C. A. Davis and C. Ellis and G. Flores and G. Franklin and C. Furget and D. Gaskell and M. T. W. Gericke and J. Grames and G. Guillard and J. Hansknecht and T. Horn and M. K. Jones and P. M. King and W. Korsch and S. Kox and L. Lee and J. Liu and A. Lung and J. Mammei and J. W. Martin and R. D. McKeown and A. Micherdzinska and M. Mihovilovic and H. Mkrtchyan and M. Muether and S. A. Page and V. Papavassiliou and S. F. Pate and 10 S. K. Phillips and P. Pillot and M. L. Pitt and M. Poelker and B. Quinn and W. D. Ramsay and J. -S. Real and J. Roche and P. Roos and J. Schaub and T. Seva and N. Simicevic and G. R. Smith and D. T. Spayde and M. Stutzman and R. Suleiman and V. Tadevosyan and W. T. H. van Oers and M. Versteegen and E. Voutier and W. Vulcan and S. P. Wells and S. E. Williamson and S. A. Wood and B. Pasquini and M. Vanderhaeghen},
journal= {arXiv preprint arXiv:1103.3667},
year = {2011}
}