ReactionCa42(p,t)Ca40at 40 MeV

Abstract

The reaction ${}_{}{}^{42}{}_{}{}^{}\mathrm{Ca}\mathrm{}(p,t)\mathrm{}{}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ at 40-MeV incident energy has been used to excite the following levels: g.s. ($0^{+}$), 3.352 ($0^{+}$), 3.734 ($3^{-}$), 3.903 ($2^{+}$), 4.487 ($5^{-}$), 5.25 ($0^{+}$, $2^{+}$, $4^{+}$), 6.51 ± 0.01, 6.62 ± 0.02, 6.945 ± 0.015, 7.575 ± 0.015, 7.69 ± 0.03 ($3^{-},T=1\mathrm{}$), 8.41 ± 0.03, 8.57 ± 0.02, 9.11 ± 0.02, and 9.30 ± 0.03. Results on the first two $0^{+}$ states are compared with theoretical predictions. There is no evidence for a 2p-2h, $0^{+}$, $T=0\mathrm{}$ state at an excitation ≲ 8 MeV, suggesting a fragmentation of this strength and/or that this state is higher in energy. The unreported ${(2\mathrm{}\mathrm{p}-2\mathrm{}\mathrm{h})}^{J=0^{+},T=1\mathrm{}}$ state has been observed at 9.30 ± 0.03 MeV. These results suggest that the monopole force discussed by Zamick is less isospin-dependent in the Ca region than is usually admitted.