Polarization transfer in quasifree (<i>p</i>→,<i>n</i>→ ) reactions at 495 MeV

Abstract

A complete set of polarization-transfer observables has been measured for quasifree (p\ensuremath{\rightarrow},n\ensuremath{\rightarrow}) reactions on $^{2}\mathrm{H}$, $^{12}\mathrm{C}$, and $^{40}\mathrm{Ca}$ at a bombarding energy of 495 MeV and a laboratory scattering angle of 18\ifmmode^\circ\else\textdegree\fi{}. The data span an energy-loss range from 0 to 160 MeV, with a corresponding momentum transfer range of ${\mathit{q}}_{\mathrm{c}.\mathrm{m}.}$=1.7--1.9 ${\mathrm{fm}}^{\mathrm{\ensuremath{-}}1}$. The laboratory observables are used to construct partial cross sections proportional to the nonspin response and three orthogonal spin responses. These results are compared to the transverse spin response measured in deep inelastic electron scattering and to nuclear responses based on the random phase approximation. The polarization observables for all three targets are remarkably similar and reveal no evidence for an enhancement of the spin-longitudinal nuclear response relative to the spin-transverse response. These results suggest the need for substantial modifications to the standard form assumed for the residual particle-hole interaction.