NUCLEAR PHYSICS A Study of the Gamow-Teller esonance

An approach is proposed for studying the spreading properties of the Gamow-Teller resonance (GTR) in heavy nuclei including the coupling to 2p2h configurations and the ground-state correlations beyond RPA. The GTR is generated by a proton p-neutron h (Trp-~h) phonon within the renormalized RPA. The second-order configuration mixing beyond RPA is realized by constructing two-phonon configurations, in which one of two intermediate phonon states is a ~rp-eh phonon. The numerical calculations are performed in the parent nuclei 9°Zr and 2°sPb making use of M3Y nucleon-nucleon interaction and the single-particle wave functions obtained in the standard harmonic oscillator potential. The single-particle energies around the Fermi surface are substituted with the empirical values or those given by a Woods-Saxon potential. The results obtained provide a reasonable account for recent experimental findings on the GTR in these nuclei. The extension of the present approach to highly excited (hot) nuclei s also provided. The GTR is found to be stable against temperatures up to T = 6 MeV. @ 1997 Elsevier Science B.V. PACS: 24.30.Cz; 21.10.Pc; 21.60.-n; 25.40.K