Charge-symmetry violation in neutron-proton elastic scattering atEn=183 MeV

Measurements of the spin dependence of n-p elastic scatteing at ${\mathit{E}}_{\mathit{n}}$=183 MeV have been carried out with polarized neutrons and polarized protons. If charge symmetry holds, the two analyzing powers ${\mathit{A}}_{\mathit{n}}$ and ${\mathit{A}}_{\mathit{p}}$ must be equal. The measured value of ΔA==${\mathit{A}}_{\mathit{n}}$-${\mathit{A}}_{\mathit{p}}$, averaged over the angular range 82.2°≤${\mathrm{\theta }}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$≤116.1°, is (33.1±5.9±4.3)×${10}^{\mathrm{-}4}$. This result represents clear evidence of charge-symmetry violation in the strong interaction. The measurement agrees well with predictions from meson-exchange theory when these include the isospin mixing of the ${\mathrm{\rho }}^0$ and ${\mathrm{\omega }}^0$ mesons.