Experimental Evidence for Proton-Pair Correlation in Ti and Cr Low-Lying Excited States

The two-proton-transfer reactions ${}_{}{}^{44,48}{}_{}{}^{}\mathrm{Ca}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$)${}_{}{}^{46,50}{}_{}{}^{}\mathrm{Ti}$ and ${}_{}{}^{48,50}{}_{}{}^{}\mathrm{Ti}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$)${}_{}{}^{50,52}{}_{}{}^{}\mathrm{Cr}$ studied at 48-MeV ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ incident energy show that the first excited states must include strong proton-pair components. It appears that the (${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$) two-proton-transfer reaction is a new and useful spectroscopic tool.