PaperPanorama
FAQ

Nuclear Theory·nucl-th

Wednesday·February 18, 2015

7 papers—6 primary·1 cross-listed

All7Primary6Cross-lists1
  1. 01

    Light-Heavy Ion Collisions: A window into pre-equilibrium QCD dynamics?

    Paul Romatschke🇺🇸

    Relativistic collisions of light on heavy ions (p+Au at sqrt(s)=7.7 GeV, p+Au, d+Au,3He+Au at sqrt(s)=62.4 GeV and 200 GeV and p+Pb, 3He+Pb at sqrt(s)=5.02 TeV) are simulated using "superSONIC", a model that includes pre-equilibrium flow, viscous hydrodynamics and a hadronic cascade afterburner. Even though these systems have strong gradients and only consist of at most a few tens of charged particles per unit rapidity, one finds evidence that a hydrodynamic description applies to these systems. Based on these simulations, the presence of a triangular flow component in d+Au collisions at sqrt(s)=200 GeV is predicted to be similar in magnitude to that found in 3He+Au collisions. Furthermore, the v3(p_T) ratio of 3He+Au to d+Au is found to be sensitive to the presence of pre-equilibrium flow. This would imply an experimentally accessible window into pre-equilibrium QCD dynamics using light-heavy ion collisions.

    nucl-thhep-phnucl-exEPJC(2015)·125 citations
  2. 02

    Energy-dependence of skin-mode fraction in excitations of neutron-rich nuclei

    H. Nakada · T. Inakura · H. Sawai

    We have extensively investigated characters of the low-energy strengths in nuclei, by analyzing the transition densities obtained by the HF+RPA calculations with several effective interactions. Crossover behavior has been confirmed, from the skin mode at low energy to the mode at higher energy. Decomposing the strengths into the skin-mode, -mode and interference fractions, we show that the ratio of the skin-mode strength to the full strength may be regarded as a generic function of the excitation energy, insensitive to nuclides and effective interactions, particularly beyond Ni.

    nucl-thEPJ Web Conf.(2015)·0 citations
  3. 03

    Particle-vibration coupling effect on the -decay of magic nuclei

    Yifei Niu · Zhongming Niu · Gianluca Colo · Enrico Vigezzi

    Nuclear -decay in magic nuclei is investigated, taking into account the coupling between particle and collective vibrations,on top of self-consistent random phase approximation calculations based on Skyrme density functionals. The low-lying Gamow-Teller strength is shifted downwards and at times becomes fragmented; as a consequence, the -decay half-lives are reduced due to the increase of the phase space available for the decay. In some cases, this leads to a very good agreement between theoretical and experimental lifetimes: this happens, in particular, in the case of the Skyrme force SkM*, that can also reproduce the line shape of the high energy Gamow-Teller resonance as it was previously shown.

    nucl-thPRL(2015)·92 citations
  4. 04

    Gamow-Teller response and its spreading mechanism in doubly magic nuclei

    Yifei Niu · Gianluca Colo · Enrico Vigezzi

    The scope of the paper is to apply a state-of-the-art beyond mean-field model to the description of the Gamow-Teller response in atomic nuclei. This topic recently attracted considerable renewed interest, due, in particular, to the possibility of performing experiments in unstable nuclei. We study the cases of Ca, Ni, Sn and Pb. Our model is based on a fully self-consistent Skyrme Hartree-Fock plus random phase approximation. The same Skyrme interaction is used to calculate the coupling between particles and vibrations, which leads to the mixing of the Gamow-Teller resonance with a set of doorway states and to its fragmentation. We compare our results with available experimental data. The microscopic coupling mechanism is also discussed in some detail.

    nucl-thPRC(2014)·56 citations
  5. 05

    Core excitation in three-body nuclear reactions: Improved nucleon-core potential

    A. Deltuva

    Three-body nuclear reactions in two-nucleon plus core systems are described in the framework of exact scattering equations including the core excitation. A nucleon-core optical potential is constructed that can be easily adjusted to the reference potential and thereby to the experimental two-body data, if available. This constitutes an important improvement over the simple deformation of the potential used previously that violated the original fit to the data. Predictions for elastic, inelastic, and transfer reactions involving and nuclear cores are obtained. The new optical potential leads to a moderate increase of cross sections.

    nucl-thnucl-exPRC(2015)·16 citations
  6. 06

    Effect of the symmetry energy and hyperon interaction on neutron stars

    Daniel Bizarro🇵🇹 · Aziz Rabhi🇵🇹 · Constança Providência🇵🇹

    The joint effect of the density dependence of the symmetry energy and strangeness content on the structure of cold neutron stars is studied within the framework of a relativistic mean field theory. It is shown that 2 are obtained for repulsive interaction and preferably for a small or a large slope . An attractive potential in nuclear matter will favor the appearance of strangeness in stars with a mass as small as , if, however it is repulsive only stars with a mass will contain strangeness. The joint effect of reducing the symmetry energy slope and including hyperons is to farther reduce the radius. Neutron star maximum mass evolve non-monotonically with the symmetry energy slope, and the smallest masses are obtained for values MeV. Other neutron star variables evolve nonlinearly with the slope of the symmetry energy and depend on the hyperon-nucleon and hyperon-hyperon couplings. The radius of a neutron star is linearly correlated with the neutron star total strangeness fraction and the slope is independent of the slope of the symmetry energy and the mass of the star.

    nucl-th8 citations
  7. 07

    Transport, Aharonov-Bohm, and Topological Effects in Graphene Molecular Junctions and Graphene Nanorings

    Constantine Yannouleas🇺🇸 · Igor Romanovsky🇺🇸 · Uzi Landman🇺🇸

    The unique ultra-relativistic, massless, nature of electron states in two-dimensional extended graphene sheets, brought about by the honeycomb lattice arrangement of carbon atoms in two-dimensions, provides ingress to explorations of fundamental physical phenomena in graphene nanostructures. Here we explore the emergence of new behavior of electrons in atomically precise segmented graphene nanoribbons (GNRs) and graphene rings with the use of tight-binding calculations, non-equilibrium Green's function transport theory, and a newly developed Dirac continuum model that absorbs the valence-to-conductance energy gaps as position-dependent masses, including topological-in-origin mass-barriers at the contacts between segments. Through transport investigations in variable-width segmented GNRs with armchair, zigzag, and mixed edge terminations we uncover development of new Fabry-Perot-like interference patterns in segmented GNRs, a crossover from the ultra-relativistic massless regime, characteristic of extended graphene systems, to a massive relativistic behavior in narrow armchair GNRs, and the emergence of nonrelativistic behavior in zigzag-terminated GNRs. Evaluation of the electronic states in a polygonal graphene nanoring under the influence of an applied magnetic field in the Aharonov-Bohm regime, and their analysis with the use of a relativistic quantum-field theoretical model, unveils development of a topological-in-origin zero-energy soliton state and charge fractionization. These results provide a unifying framework for analysis of electronic states, coherent transport phenomena, and the interpretation of forthcoming experiments in segmented graphene nanoribbons and polygonal rings.

    ↳ cond-mat.mes-hallcond-mat.mtrl-scihep-phnucl-thJ.Phys.Chem.(2015)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE