On the Bump at High Excitation in Sn (p, t) Reactions

In recent (p, t) experiments, 1) a bump has been observed around 89 MeV excitation in Sn isotopes. The authors in Ref. 1) interpreted the bump in terms of deep-lying ('high-lying' in the same meaning) pairing vibration indicated in Fig. 1(a). This interpretation predicts, however, the excitation around 11 MeV of the bump in Sn isotopes, leaving 23 MeV discrepancy in excitation energy, since deep-lying onehole state is observed around 5.5 MeV excitation. 2),S) The linear dependence of excitation as to the number of holes is correct even if isospin symmetry of hole states4) is taken into account. Only the difference in pairing correlation between two holes in Fig. 1 (a) and that of the cor-