title: Measuring the P-odd pion-nucleon coupling h((1))(piNN) in pi(+)-photoproton production near threshold.
abstract: We show that gamma-->p-->pi(+)n in the threshold region is an excellent candidate for measuring the leading parity-violating pion-nucleon coupling h((1))(piNN) to an uncertainty of 20% if it has a natural size from dimensional analysis. The conclusion is based on a large unpolarized cross section, a new low-energy theorem for the photon polarization asymmetry at the threshold A(gamma)/(th) = square root of 2 f(pi)(mu(p)-mu(n))h((1))(piNN)/g(A)m(N) approximately h((1))(piNN)/2, and its strong dominance at forward and backward angles in the threshold region.
authors.affiliation: Department of Physics, University of Maryland, College Park, Maryland 20742-4111, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Chen
authors.forename: X
authors.initials: X
authors.lastname: Ji