π+−pElastic Scattering at 310 Mev: Recoil-Nucleon Polarization

Abstract

The recoil-proton polarization in ${\pi }^{+}-p$ elastic scattering at 310-Mev incident-pion laboratory kinetic energy has been experimentally measured at four scattering angles with scintillation counters. Polarization values obtained, related rms experimental errors, and mean center-of-mass recoil angles are: +0.044±0.062 at 114.2 deg, -0.164±0.057 at 124.5 deg, -0.155±0.044 at 133.8 deg, and -0.162±0.037 at 145.2 deg. The sign of the polarization is defined to be positive when a preponderance of the recoil protons had their spin vectors pointing in the direction of ${\mathrm{p}}_i\times {\mathrm{p}}_f$, where this quantity is the cross product of the initial and final momentum vectors of the conjugate pions. A beam of 1×${10}^6$ pions per sec incident upon a 1.0-g/${\mathrm{cm}}^2$-thick liquid-hydrogen target produced the recoil protons, which were then scattered by a carbon target at a mean energy varying with recoil angle from 113 to 141 Mev. The polarization of the recoil protons was analyzed by measuring the asymmetry produced in the carbon scattering. A proton beam of known polarization was used to determine the analyzing ability (measured asymmetry divided by the polarization of the incident protons) of the system at each recoil angle. Values obtained for the analyzing ability range from 0.41 to 0.57.R where this quantity is the cross product of the initial and final momentum vectors of the conjugate pions. A beam of 1×${10}^6$ pions per sec incident upon a 1.0-g/${\mathrm{cm}}^2$-thick liquid-hydrogen target produced the recoil protons, which were then scattered by a carbon target at a mean energy varying with recoil angle from 113 to 141 Mev. The polarization of the recoil protons was analyzed by measuring the asymmetry produced in the carbon scattering. A proton beam of known polarization was used to determine the analyzing ability (measured asymmetry divided by the polarization of the incident protons) of the system at each recoil angle. Values obtained for the analyzing ability range from 0.41 to 0.dat