π−−pElastic Scattering at 310 MeV: Differential Cross Section and Recoil-Proton Polarization

The differential cross section and recoil-proton polarization in ${\pi }^{-}-p$ elastic scattering at 310-MeV incident-pion energy has been measured. The differential cross section was measured at 28 angles in the angular region $25<~{\theta }_{\mathrm{lab}}<~160$ deg. The fractional rms errors were typically 3%. The reaction was observed by counting the scattered pions emerging from a liquid-hydrogen target with a counter telescope consisting of scintillation and Čerenkov counters. Simultaneously, the recoil-proton polarization was measured at four angles in the angular region $114<\mathrm{}{\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}<146\mathrm{}$ deg. The recoil protons from the liquid-hydrogen target were scattered from a carbon target and the left-right asymmetry was measured. Scintillation counters were used throughout to detect the particles.