Microscopic study of Gamow-Teller and spin-dipole states in
1 Department of Physics, College of Humanities and Sciences,
Nihon University Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156, Japan
2 Center for Mathematical Sciences,
the University of Aizu Aizu-Wakamatsu, Fukushima 965, Japan
Received: 11 April 2000 / Revised version: 1 August 2000
Communicated by: P. Schuck
Abstract
Gamow-Teller (GT) and
spin-dipole (SD) states in 208Bi are studied by using
self-consistent Hartree-Fock + Tamm-Dancoff approximation taking
into account the coupling to the continuum.
Most of SD strength is found at the
excitation energy
with a very broad width,
which agrees with recent experimental observations.
It is shown that
Landau damping effect is responsible for the
large width of SD peak, while the escape width is
found to be at most 1MeV.
We study also electric dipole (E1) transitions between GT and
SD states in 208Bi. Main E1 transitions for 0- and 1-states are found near excitation energy expected from Brink's
hypothesis in which SD states are considered as E1 resonances built on the GT state.
Calculated E1 transition strengths between GT and SD states are compared with the analytic
sum rules within one-particle one-hole (1p-1h) configuration space
and within both 1p-1h and 2p-2h model space.
PACS
24.30.Cz Giant resonances
- 21.10.Pc Single-particle levels and strength functions
- 23.20.Lv Gamma transitions and level energies
- 21.60.Jz Hartree-Fock and random-phase approximations
Copyright Società Italiana di Fisica, Springer-Verlag 2000
