Gamow-Teller transition strengths in the intermediate nucleus of the116Cd double-βdecay by the116Cd(p,n)116In and116Sn(n,p)116In reactions at 300 MeV

The double-differential cross sections for the ${}^{116}$Cd$(p,\phantom{\rule{-0.16em}{0ex}}n)$ and ${}^{116}$Sn$(n,\phantom{\rule{-0.16em}{0ex}}p)$ reactions were measured at 300 MeV for studying the nuclear matrix element of the ${}^{116}$Cd $\ensuremath{\beta}\ensuremath{\beta}$ decay. A multipole decomposition technique was applied to the spectra to extract the Gamow-Teller (GT) component. The integrated GT strengths up to an excitation energy of 30 MeV in the intermediate nucleus ${}^{116}$In are $40\ifmmode\pm\else\textpm\fi{}6$ and $11\ifmmode\pm\else\textpm\fi{}1$ in the $(p,\phantom{\rule{-0.16em}{0ex}}n)$ and $(n,\phantom{\rule{-0.16em}{0ex}}p)$ spectra, respectively, including the component from the isovector spin monopole (IVSM). The spectra are compared with those obtained from a theoretical calculation with a quasiparticle random phase approximation, where the contribution from the IVSM component as well as the interference effect between the GT and IVSM components are fully taken into account.