Publication View

Transverse beam spin asymmetries in forward-angle elastic electron-proton scattering (2007)

Abstract
We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 values of 0.15 and 0.25 (GeV/c)^2 with results of A_n = -4.06 +- 0.99 (stat) +- 0.63 (syst) and A_n = -4.82 +- 1.87 (stat) +- 0.98 (syst) ppm. These 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 2-gamma exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.

Publication details
Download http://hal.in2p3.fr/in2p3-00147801/en/
Publisher HAL - CCSd - CNRS
Contributors Claudine Tur
Repository CCSd/HAL : e-articles server (based on gBUS) (France)
Keywords Physics/High Energy Physics - Phenomenology, Physics/Nuclear Experiment
Coverage Elastic electron scattering; elastic and compton scattering; electromagnetic processes and properties; protons; neutrons