First Observation of $P$-odd $\gamma$ Asymmetry in Polarized Neutron Capture on Hydrogen

D. Blyth, J. Fry, N. Fomin +61

We report the first observation of the parity-violating 2.2 MeV gamma-ray asymmetry $A_{\gamma }^{np}$ in neutron-proton capture using polarized cold neutrons incident on a liquid parahydr…