Fermi and Gamow-Teller strength in p-shell nuclei from (p,n) reactions at 492 and 590 MeV

Zero-degree (p,n) cross sections, measured with approximately 1-MeV energy resolution at $E_p$=492 MeV, are reported for ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$, and ${}_{}{}^{12}{}_{}{}^{}$,13,14C. Measurements for ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$(p,n) and ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$(p,n) were also obtained at 590 MeV. The cross sections for Gamow-Teller and Fermi type transitions are used to estimate the strengths of the isovector spin-dependent ($J_{\sigma \tau }$) and spin-independent ($J_{\tau }$) terms of the effective interaction. The measured zero-degree cross sections for the ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$(p,n${)}^{14}$N transitions to the 2.31 MeV isobaric analog state and the 3.95-MeV $J^{\pi }$${=1\mathrm{}}^{+}$ state are compared with calculated values. Values for the unit cross-section ratio $R^2$=σ${^}_{\mathrm{GT}}$/σ${^}_F$ =($J_{\sigma \tau }$/$J_{\tau }$${)}^2$ ($N_{\sigma \tau }$/$N_{\tau }$) obtained from the present data are compared with results for other energies.