We study the possibility of measuring parity-violating pion-nucleon coupling h_{ \pi NN}^{ (1)} from \pi^+ electroproton production in the threshold region. We calculate the electron-helicity asymmetry in terms of h_{ \pi NN}^{ (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.
Categories: nucl-th