Partonic calculation of $\gamma Z$ Exchange Corrections to Parity-Violating Elastic Electron-Proton Scattering

Abstract

We calculate $\gamma Z$ exchange corrections to the parity-violating asymmetry of the elastic electron-proton scattering in a parton model using the formalism of generalized parton distributions(GPDs). We also examine the validity of the zero-momentum-transfer approximation adopted in the literatures and find that it overestimates the $\gamma Z$ exchange effect significantly at the forward scattering angles.

Comments: 4pages, 5 figs