Effective IsovectorNNInteraction Strengths Determined from theS28i(p→,p→′)S28i(6−,T=1)Reaction

Abstract

We report measurements of $\ensuremath{\sigma}(\ensuremath{\theta})$, $A(\ensuremath{\theta})$, and polarization transfer for the $^{28}S\mathrm{i}(\stackrel{\ensuremath{\rightarrow}}{p},{\stackrel{\ensuremath{\rightarrow}}{p}}^{\ensuremath{'}})^{28}S\mathrm{i}$ reaction to the ${6}^{\ensuremath{-}},T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1$ state at 14.36 MeV initiated with 198 MeV polarized protons. Normalization of the transition strength in the distorted-wave impulse approximation (DWIA) to inelastic electron scattering overpredicts the spin-longitudinal cross section by more than a factor of 2, while the spin-transverse cross section is nearly correct and the spin-orbit cross section is underpredicted. A reduced in-medium $\ensuremath{\rho}$-meson mass reproduces some of these features, while strong relativistic mean field or Pauli blocking effects are too small.