Momentum Dependence of the Nuclear Isovector Spin Responses from (p→,n→) Reactions at 494 MeV

Complete sets of polarization transfer coefficients have been measured for quasifree ($\overrightarrow{p},\overrightarrow{n}$) scattering from ${}_{}{}^2{}_{}{}^{}\mathrm{H}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ at 494 MeV and scattering angles of 12.5°, 18°, and 27° ($q=1.2, 1.7, 2.5$ ${\mathrm{fm}}^{-1\mathrm{}}$). These measurements yield separated transverse ($\sigma \times q$) and longitudinal ($\sigma ·q$) isovector spin responses. Comparison of the separated responses to calculations and to electron-scattering responses reveals a strong enhancement in the spin transverse channel. This excess transverse strength masks the effect of pionic correlations in the response ratio.