Tensor correlation effects on Gamow-Teller resonances in 120Sn and N=80, 82 isotones

We develop a separable-type tensor interaction in the finite rank separable approximation, which enables us to perform a quasiparticle random phase approximation (QRPA) calculation in a very large two-quasiparticle space without too much computational burden. The validity of the model is checked in comparison with exact QRPA calculations with full Skyrme interaction SGII with tensor terms. The model is then applied to study the tensor effect on the Gamow-Teller (GT) strength distribution of Sn-120. We also calculate the GT states in open shell N = 80 and 82 isotones, Cd-128,130(48), Sn-130,132(50), and Te-132,134(52). The QRPA results calculated by the separable interactions with the tensor terms show that the tensor correlations lead to a redistribution of the main GT strength to lower energy peaks and also to higher energy tails. The increase of the sum rule strength in both the sigma tau- and sigma tau+ channels is also indicated by the QRPA with tensor correlations.