High-lying0+and3−levels inC12

Abstract

The $\ensuremath{\gamma}$ decays of the levels at 17.77 and 18.36 MeV in $^{12}\mathrm{C}$ are studied by proton capture and the assignments of (${0}^{+}$,1) and (${3}^{\ensuremath{-}}$,1), respectively, are confirmed. The very great strength of the decay of the (${0}^{+}$,1) level to the lower (${1}^{+}$,0) level at 12.71 MeV is consistent with a spin- and isospin-flip deuteronlike transition. The strong decay of the (${3}^{\ensuremath{-}}$,1) level to the lower (${3}^{\ensuremath{-}}$,0) level at 9.64 MeV is fairly typical of an analog to antianalog transition. The $\ensuremath{\gamma}$-decay widths of these levels are compared with shell-model calculations.NUCLEAR REACTIONS $^{11}\mathrm{B}$($p$,$\ensuremath{\gamma}$)$^{12}\mathrm{C}$, ${E}_{p}=0.82\ensuremath{-}2.83$ MeV. Measured excitation functions and angular distributions of resonances at 17.77 and 18.36 MeV; deduced spins, parities, and transition strengths to levels at 12.71 and 9.64 MeV, respectively. Enriched targets.