Self-Consistent Calculations of Probabilities for the E1 Transition between the Ground State and the [3-1x2+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 E1 transitions between the ground state and the [3(1)(-)x2(1)(+)]1- two-phonon state in the semimagic tin isotopes Sn104-124. 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 Sn-112, is obtained. Values of B(E1) are predicted for Sn-104-110,Sn-114 even-even nuclei. It is shown that dynamical ground-state three-quasiparticle correlations make a substantial contribution to the reduced probabilities for the E1 transitions in question, so that their inclusion is necessary for explaining experimental data.