Effects of a Skyrme-type tensor force on the spin-isospin excitations

¹ Department of Physics, Sichuan University, Chengdu 610065, China
² China Institute of Atomic Energy, China
³ Center for Mathematics and Physics, University of Aizu, Aizu-Wakamatsu, Fukushima 965-8560, Japan
⁴ RIKEN, Nishina Center, Wako 351-0198, Japan
⁵ Dipartimento di Fisica, Università degli Studi di Milano and INFN, Sezione di Milano, 20133 Milano, Italy
⁶ School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, China

^a e-mail: bclphy@scu.edu.cn

Published online: 20 March 2014

Abstract

The effects of the tensor force on the charge-exchange Gamow-Teller (GT) and spin-dipole (SD) states are studied by using the self-consistent Hartree-Fock plus Random Phase Approximation (HF+RPA) approach based on Skyrme zero-range forces. We have found, not surprisingly, that the tensor force has a large effect on the GT strength. In the case of the SD excitations, the tensor force produces a softening of the 1⁻ states, but a hardening of 0⁻ and 2⁻ states: these effects improve the agreement with the experimental findings. We have also studied how to constrain the magnitude of the tensor terms of the Skyrme interaction by using the empirical information on the collective GT and SD excited states in ⁹⁰Zr and ²⁰⁸Pb.