On the Fermi and Gamow-Teller strength distribution in medium-heavy mass nuclei

Abstract

An isospin-selfconsistent approach based on the Continuum-Random-Phase-Approximation (CRPA) is applied to describe the Fermi and Gamow-Teller strength distributions within a wide excitation-energy interval. To take into account nucleon pairing in open-shell nuclei, we formulate an isospin-selfconsistent version of the proton-neutron-quasiparticle-CRPA (pn-QCRPA) approach by incorporating the BCS model into the CRPA method. The isospin and configurational splittings of the Gamow-Teller giant resonance are analyzed in single-open-shell nuclei. The calculation results obtained for ${}^{208}$Bi, ${}^{90}$Nb, and Sb isotopes are compared with available experimental data.

Comments: 22 pages, 3 tables, 4 figures, to be published in Physics of Atomic Nuclei