Measuring the P-odd pion-nucleon coupling hπNN(1) in π+-Photoproton production near threshold
Journal
Physical Review Letters
Journal Volume
86
Journal Issue
19
Pages
4239-4242
Date Issued
2001
Author(s)
Ji, X.
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.
SDGs
Type
journal article