Electron Beam Single-Spin Asymmetries in the Resonance Region with Final   Hadrons Observed
  We study beam-transverse and normal single-spin asymmetry for electron-proton inelastic scattering in the resonance region for the case where a pion is observed in the final state. There is no beam single-spin asymmetry if the observed particle has single-photon exchange as its only interaction, but this is naturally circumvented when one observes a strongly interacting final state particle. The asymmetries are not large as there is an electron mass divided by momentum transfer suppression. We present results for the cases where the final electron and a pion are both observed, with asymmetries of order tens of ppm, and where only a final pion is observed, with asymmetries of order one ppm. 
Brandon Buncher and Carl E. Carlson (William and Mary)
hep-ph nucl-th