Parity-Violating Pion-Nucleon Coupling h_{πNN}^{(1)} from π^+ Electroproton Production Near the Threshold

Abstract

We study the possibility of measuring parity-violating pion-nucleon coupling h_{πNN}^{(1)} from π^+ electroproton production in the threshold region. We calculate the electron-helicity asymmetry in terms of h_{πNN}^{(1)} and the Z-boson exchange between the electron and proton in leading-order heavy-baryon chiral perturbation theory. From the result, we demonstrate that the coupling can be determined to an accuracy of about 2 10^{-7} in an experiment with incident electron energy 250 MeV, luminosity 10^{38} sec^{-1} cm^{-2}, and a running time of 10^7 sec.

9 pages and 6 figures