Self-Consistent Calculations of Probabilities for the E 1 Transition Between the Ground State and the [3_1^-× 2_1^+]_1^- Two-Phonon State in Tin Isotopes

A self-consistent method for studying second-order anharmonic effects on the basis of many-body quantum field theory is applied for the first time in calculating probabilities for E 1 transitions between the ground state and the [3_1^-× 2_1^+]_1^- two-phonon state in the semimagic tin isotopes ^104-124 Sn. The approach used involves taking into account (i) self-consistency of the nuclear mean field and effective interaction on the basis of the energy density functional method with the parameters of the Fayans functional DF3-a, which were earlier found to provide good results; (ii) ground-state three-quasiparticle correlations; and (iii) nuclear-polarizablility effects. Good agreement with available experimental data, including those for ^112 Sn, is obtained. Values of B ( E 1) are predicted for ^104-110,114 Sn even–even nuclei. It is shown that dynamical ground-state three-quasiparticle correlations make a substantial contribution to the reduced probabilities for the E 1 transitions in question, so that their inclusion is necessary for explaining experimental data.