Measurement Of Parity-Violating Gamma-Ray Asymmetry In Compound Nuclei With Cold Neutrons

The NPDGamma collaboration has constructed and commissioned an apparatus on flight path 12 at LANSCE to measure with a high precision, 5x10(-9), the small parity-violating gamma-ray asymmetry, A(gamma), in polarized neutron capture on protons. This asymmetry can be determined unambiguously the weak pion-nucleon coupling constant. To study the hadronic weak interaction at low energy, the collaboration has used the NPDGamma apparatus to measure parity-violating gamma-ray asymmetries in compound nuclei with cold neutrons. Using the statistical model of compound nuclei and spectroscopic information of the target nuclei, we can set upper limit on the spreading width of the hadronic weak interaction for intermediate-mass nuclei. We describe the experiment and the preliminary results of measured gamma-ray asymmetries of Al, Sc, Ti, Mn, and Co.