2016/05/31 by Caroline Robin, Елена Литвинова, Elena Litvinova · 57 citations
Engineering · Physics and Astronomy · #Atomic physics #Isospin #Neutron #Nuclear physics #Nuclear physics research studies #Nuclear reactor physics and engineering #Phonon #Physics #Pion #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Quasiparticle #Random phase approximation #Resonance (particle physics) #Scattering #Spin (aerodynamics) #Spin-flip #nucl-th
paper · pdf · doi:10.1140/epja/i2016-16205-0
published in The European Physical Journal A 52(7) (Springer Science+Business Media) · 14 pages, 11 figures. v3: convergence study added, other minor corrections and references added, version accepted for publication in The European Physical Journal A as part of the topical issue "Finite range effective interactions and associated many-body methods - A tribute to Daniel Gogny". The final publication is available at Springer via http://dx.doi.org/10.1140/epja/i2016-16205-0
openalex created_date 2016/06/24 · openalex publication_date 2016/07/01 · arxiv created 2016/07/29 · arxiv updated 2016/08/01 · openalex updated_date 2026/08/05
A new theoretical approach to spin-isospin excitations in open-shell nuclei is presented. The developed method is based on the relativistic meson-exchange nuclear Lagrangian of Quantum Hadrodynamics and extends the response theory for superfluid nuclear systems beyond relativistic quasiparticle random phase approximation in the proton-neutron channel (pn-RQRPA). The coupling between quasiparticle degrees of freedom and collective vibrations (phonons) introduces a time-dependent effective interaction, in addition to the exchange of pion and ρ-meson taken into account without retardation. The time-dependent contributions are treated in the resonant time-blocking approximation, in analogy to previously developed relativistic quasiparticle time blocking approximation (RQTBA) in the neutral (non-isospin-flip) channel. The new method is called proton-neutron RQTBA (pn-RQTBA) and applied to Gamow-Teller resonance in a chain of neutron-rich Nickel isotopes 68-78Ni. A strong fragmentation of the resonance along with quenching of the strength, as compared to pn-RQRPA, is obtained. Based on the calculated strength distribution, beta-decay half-lives of the considered isotopes are computed and compared to pn-RQRPA half-lives and to experimental data. It is shown that a considerable improvement of the half-life description is obtained in pn-RQTBA because of the spreading effects, which bring the lifetimes to a very good quantitative agreement with data.