Darmstadt 2008 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 14: Theorie
HK 14.4: Group Report
Monday, March 10, 2008, 17:30–18:00, 2F
Nuclear structure calculations beyond the relativistic QRPA for astrophysical applications — •Elena Litvinova1, Peter Ring2,3, Victor Tselyaev4, Dario Vretenar5,2, Karlheinz Langanke1, Gabriel Martinez-Pinedo1, and Hans Peter Loens1 — 1GSI, Darmstadt, Germany — 2TUM, Garching, Germany — 3Universidad Autónoma de Madrid, Madrid, Spain — 4St. Petersburg State University, St. Petersburg, Russia — 5University of Zagreb, Zagreb, Croatia
The Relativistic Quasiparticle Time Blocking Approximation (RQTBA) developed recently is presented. The physical content of the RQTBA is the self-consistent Relativistic QRPA supplemented with the quasiparticle-phonon coupling within the quasiparticle time blocking approximation.
The description of electric dipole excitations in the even-even spherical neutron-rich nuclei is performed within the RQTBA. Coupling to collective vibrations generates spectra with a multitude of two quasiparticles-phonon states providing a noticeable fragmentation of the giant dipole resonance and a spreading of the pygmy resonance to lower energies that agrees very well with experimental data. Properties of the low-lying dipole strength below and around the one-nucleon separation energy are investigated within our approach. The influence of the pygmy resonance on (n,γ)-reaction cross sections and reaction rates has been studied within the Hauser-Feshbach model. The (n,γ) cross sections can be strongly enhanced which has a pronounced influence on the r-process abundance distribution.