Parity nonconservation in proton-water scattering at 800 MeV

A search has been made for parity nonconservation in the scattering of 800 MeV polarized protons from an unpolarized water target. The result for the longitudinal asymmetry is AL=+(6.6±3.2)×10−7. Control runs with Pb, using a thickness that gave equivalent beam broadening from multiple Coulomb scattering, but a factor of ten less nuclear interactions than the water target, gives AL=−(0.5±6.0)×10−7.