Elastic Scattering of 146-Mev Polarized Protons by Deuterons

Abstract

The polarization and differential cross section of 146-Mev protons elastically scattered by deuterons have been measured in the center-of-mass angular range from 3.9\ifmmode^\circ\else\textdegree\fi{} to 170\ifmmode^\circ\else\textdegree\fi{}. A description of the liquid deuterium target and detection apparatus which permitted the measurement of the elastic events over these angles is given. At small angles the proton was energy analyzed; at large angles the recoil partner of the proton, the deuteron, was identified and energy analyzed. Although the energy resolution of \ifmmode\pm\else\textpm\fi{}1.7 Mev and the angular resolution of \ifmmode\pm\else\textpm\fi{}2.0\ifmmode^\circ\else\textdegree\fi{} were sufficient to separate quasi-elastic events from elastic events at most angles, they were insufficient to resolve unambiguously the 2.3-Mev inelastic events resulting from the formation of virtual deuterons. The measured cross section is in qualitative agreement with cross sections at neighboring energies; no comparison of measured polarizations is possible due to the lack of other experiments. The cross sections and polarization for angles less than 80\ifmmode^\circ\else\textdegree\fi{} c.m. are well fitted by the Kerman, McManus, and Thaler theory using the Gammel and Thaler nucleon-nucleon potential description. The energy and angular dependence of the large-angle pickup cross section proposed by Chew and Goldberger agree well with experiment; however, the small measured positive polarization is not predicted by this theory, and probably indicates destructive interference between the direct and the pickup scattering.