Parity Violation in Proton-Proton Scattering at 221 MeV

Abstract

The parity-violating longitudinal analyzing power, ${A}_{z}$, has been measured in $\stackrel{\ensuremath{\rightarrow}}{p}p$ elastic scattering at an incident proton energy of 221 MeV. The result obtained is ${A}_{z}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}[0.84\ifmmode\pm\else\textpm\fi{}0.29(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.17(\mathrm{syst})]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$. This experiment is unique in that it selects a single parity violating transition amplitude ${(}^{3}{P}_{2}^{1}\ensuremath{-}D_{2})$ and consequently directly constrains the weak meson-nucleon coupling constant ${h}_{\ensuremath{\rho}}^{\mathrm{pp}}$. When this result is taken together with the existing $\stackrel{\ensuremath{\rightarrow}}{p}p$ parity violation data, the weak meson-nucleon coupling constants ${h}_{\ensuremath{\rho}}^{\mathrm{pp}}$ and ${h}_{\ensuremath{\omega}}^{\mathrm{pp}}$ can, for the first time, both be determined.