Gamow-Teller unit cross sections of the (p,n) reaction at 198 and 297 MeV on medium-heavy nuclei

Gamow-Teller (GT) unit cross sections, sigma(GT), are obtained at 198 and 297 MeV by measuring the double differential cross sections at 0(degrees) for the (p,n) reaction on Ni-58, Zn-70, Cd-114, Sn-118, and Sn-120. The mass dependence of sigma(GT) and the ratio of sigma(GT) to the Fermi unit cross section, sigma(F), (R-2) are also derived in the mass region of 58 <= A <= 120. The sigma(GT) value for Zr-90 at 297 MeV interpolated using the A-dependence obtained herein agrees with that used in a previous analysis where the GT transition strength over a wide energy region up to the continuum was discussed. However, the deduced Ni-64 sigma(GT) value at 198 MeV is 20% smaller than that obtained from the analysis of a previous (n,p) measurement. The present R-2 values in the mass region heavier than Ca-42 are larger than those in the region up to Ca-42 and increase as a function of A.