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Nuclear Theory·nucl-th

Wednesday·May 4, 2016

9 papers—6 primary·3 cross-listed

All9Primary6Cross-lists3
  1. 01

    Nuclear response theory for spin-isospin excitations in a relativistic quasiparticle-phonon coupling framework

    Caroline Robin🇺🇸 · Elena Litvinova🇺🇸

    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 -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 Ni. 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.

    nucl-thEPJA(2016)·59 citations
  2. 02

    Beyond mean-field boson-fermion model for odd-mass nuclei

    K. Nomura · T. Nikšić · D. Vretenar

    A novel method for calculating spectroscopic properties of medium-mass and heavy atomic nuclei with an odd number of nucleons is introduced, based on the framework of nuclear energy density functional theory and the particle-core coupling scheme. The deformation energy surface of the even-even core, as well as the spherical single-particle energies and occupation probabilities of the odd particle(s), are obtained in a self-consistent mean-field calculation determined by the choice of the energy density functional and pairing interaction. This method uniquely determines the parameters of the Hamiltonian of the boson core, and only the strength of the particle-core coupling is specifically adjusted to selected data for a particular nucleus. The approach is illustrated in a systematic study of low-energy excitation spectra and transition rates of axially deformed odd-mass Eu isotopes.

    nucl-thPRC(2016)·46 citations
  3. 03

    Algebraic benchmark for prolate-oblate coexistence in nuclei

    A. Leviatan · D. Shapira

    We present a symmetry-based approach for prolate-oblate and spherical-prolate-oblate shape coexistence, in the framework of the interacting boson model of nuclei. The proposed Hamiltonian conserves the SU(3) and symmetry for the prolate and oblate ground bands and the U(5) symmetry for selected spherical states. Analytic expressions for quadrupole moments and rates involving these states are derived and isomeric states are identified by means of selection rules.

    nucl-thnucl-exquant-phPRC(2016)·23 citations
  4. 04

    Microscopic analysis of p^{10}B scattering at the intermediate energies

    Albert Dzhazairov-Kahramanov · Elena Ibraeva · Pavel Krassovitskiy

    The differential cross sections of the p^{10}B scattering at energies of 197, 600 and 1000 MeV have been calculated within the framework of the Glauber theory. The operator of multiple scattering takes into account the contributions of single and double collisions. The contributions from protons scattering on the nucleons of different shells have been estimated in the single-scattering cross-section. The comparison with the experiment at 197 MeV and with DWBA calculation showed the adequate description of cross-sections in the region of the front angles.

    nucl-th0 citations
  5. 05

    Multidimensionally-constrained covariant density functional theories --- nuclear shapes and potential energy surfaces

    Shan-Gui Zhou

    The intrinsic nuclear shapes deviating from a sphere not only manifest themselves in nuclear collective states but also play important roles in determining nuclear potential energy surfaces (PES's) and fission barriers. In order to describe microscopically and self-consistently nuclear shapes and PES's with as many shape degrees of freedom as possible included, we developed multidimensionally-constrained covariant density functional theories (MDC-CDFTs). In MDC-CDFTs, the axial symmetry and the reflection symmetry are both broken and all deformations characterized by with even are considered. We have used the MDC-CDFTs to study PES's and fission barriers of actinides, the non-axial octupole correlations in isotones and shapes of hypernuclei. In this Review we will give briefly the formalism of MDC-CDFTs and present the applications to normal nuclei.

    nucl-thnucl-exPhys.Scripta(2016)·133 citations
  6. 06

    Transition from direct to sequential two-proton decay in - shell nuclei

    T.A. Golubkova · X. Xu · L.V. Grigorenko · I.G. Mukha · C. Scheidenberger · M.V. Zhukov

    Transitions among different mechanisms of two-proton decay are studied in general. The introduced improved direct-decay model generalizes the semi-analytical models used before and provides flawless phenomenological description of three-body correlations in decays. This is demonstrated by examples of the low-lying Ne state decays. Different forms of transition dynamic are shown to be highly probable beyond the proton dripline for the - shell nuclei. It is demonstrated that transition dynamic of emitters can provide means for extraction of a width of the ground-state resonance of a core+ subsystem of the core+ system. Practical applicability of the method is demonstrated by properties of the F ground state derived from the decay data and of the Cl ground state derived from the decay data.

    nucl-thPLB(2016)·17 citations

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first authorsco-authorsvia INSPIRE