Single--Spin Asymmetries in the Bethe--Heitler Process $e^- + p \to e^-   + \gamma + p$ from QED Radiative Corrections
  We derived analytic formulae for the polarization single--spin asymmetries (SSA) in the Bethe--Heitler process $e^- + p \to e^- + \gamma + p$. The asymmetries arise due to one-loop QED radiative corrections to the leptonic part of the interaction and present a systematic correction for the studies of virtual Compton Scattering on a proton through interference with the Bethe-Heitler amplitude. Considered are SSA with either longitudinally polarized electron beam or a polarized proton target. The computed effect appears to be small, not exceeding 0.1 per cent for kinematics of current virtual Compton scattering experiments. 
Andrei V. Afanasev, M.I. Konchatnij and N.P. Merenkov