Anomalous Two-Phonon (p,t) Transitions in Cadmium

Abstract

Data were obtained for ($p,t$) reactions on ${\mathrm{Cd}}^{112,114,116}$, with $E_p=27.9\mathrm{}$ MeV. The angular distributions for $J^{\pi }=0^{+} \mathrm{and} 2^{+}$ two-phonon states differ markedly in phase from zero-and one-phonon transitions. The ratios of cross sections to the $2^{+}$ states are systematically an order of magnitude larger than expected from $B\left(E2\mathrm{}\right)\mathrm{}$ ratios. Two-step mechanisms are suggested.