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Nuclear Theory·nucl-th

Monday·June 15, 2015

9 papers—6 primary·3 cross-listed

All9Primary6Cross-lists3
  1. 01

    [Submitted on 11 Jun 2015]

    Hydrodynamic Approaches in Relativistic Heavy Ion Reactions

    Rafael Derradi de Souza🇧🇷 · Tomoi Koide🇧🇷 · Takeshi Kodama🇧🇷

    We review several facets of the hydrodynamic description of the relativistic heavy ion collisions, starting from the historical motivation to the present understandings of the observed collective aspects of experimental data, especially those of the most recent RHIC and LHC results. In this report, we particularly focus on the conceptual questions and the physical foundations of the validity of the hydrodynamic approach itself. We also discuss recent efforts to clarify some of the points in this direction, such as the various forms of derivations of relativistic hydrodynamics together with the limitations intrinsic to the traditional approaches, variational approaches, known analytic solutions for special cases, and several new theoretical developments. Throughout this review, we stress the role of course-graining procedure in the hydrodynamic description and discuss its relation to the physical observables through the analysis of a hydrodynamic mapping of a microscopic transport model. Several questions to be answered to clarify the physics of collective phenomena in the relativistic heavy ion collisions are pointed out.

    Comments:
    73 pages, 15 figures. Improved text and a few references added. Accepted for publication in Progress in Particle and Nuclear Physics
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1506.03863 [pdf]
    PPNP(2016)·206 citations
  2. 02

    [Submitted on 12 Jun 2015]

    Towards experimental search for the atomic effect in alpha decay: comparison of the adiabatic approach with the frozen shell model

    Feodor F. Karpeshin · Malvina B. Trzhaskovskaya

    We study the important for the experiment features of the effect of the electron shell on alpha decay in the adiabatic approach. The effect is of tenths of a percent or less in magnitude, depending on the transition energy and the atomic number. On the other hand, we show the predominant role of the inner shells: more than 80% of the effect are due to the 1s electrons. This fact is crucial for the experiment, allowing one to perform measurements in the same storage rings, comparing for example, the probability of decay in the bare nuclei and Helium-like ions. The analysis is presented concerning the reasons for the relative success and the limits of applicability of the model of "frozen" electron shell used to calculate the effect for more than half a century.

    Comments:
    19 pages, in Russian, 2 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1506.04032 [pdf]
    0 citations
  3. 03

    [Submitted on 12 Jun 2015]

    New insights on the hyperon puzzle from quantum Monte Carlo calculations

    Francesco Pederiva🇮🇹 · Francesco Catalano🇸🇪 · Diego Lonardoni🇮🇹 · Alessandro Lovato🇺🇸 · Stefano Gandolfi🇺🇸

    In the last years auxiliary field diffusion Monte Carlo has been used to assess the properties of hypernuclear systems, from light- to medium-heavy hypernuclei and hyper-neutron matter. One of the main findings is the key role played by the three-body hyperon-nucleon-nucleon interaction in the determination of the hyperon separation energy of hypernuclei and as a possible solution to the hyperon puzzle. However, there are still aspects of the employed hypernuclear potential that remain to be carefully investigated. In this paper we show that the isospin dependence of the Lambda-NN force, which is crucial in determining the NS structure, is poorly constrained by the available experimental data.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1506.04042 [pdf]
    6 citations
  4. 04

    [Submitted on 12 Jun 2015]

    A Study of Shell Model Neutron States in Using the Generalized Woods-Saxon plus Spin-Orbit Potential

    J. A. Liendo🇻🇪 · E. Castro🇻🇪 · R. Gómez🇻🇪 · D. D. Caussyn🇺🇸

    The experimental binding energies of single-particle and single-hole neutron states belonging to neutron shells that extend from N = 126 to 184 and 82 to 126 respectively, have been reproduced by solving the Schrödinger equation with a potential that has two components: the generalized Woods-Saxon (GWS) potential and the spin-orbit (SO) coupling term. The GWS potential contains the traditional WS potential plus a term (SU) whose intensity reaches a maximum in the nuclear surface. Our results indicate the existence of a explicit relationship between the strength of the SU potential and the orbital angular momentum quantum number of the state. This dependence has been used to make reasonable predictions for the excitation energy centroids of states located inside and outside the neutron shells investigated. Comparisons are made with results reported in previous investigations.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1506.04055 [pdf]
    IJMPE(2016)·6 citations
  5. 05

    [Submitted on 12 Jun 2015]

    Lepton polarization asymmetries for FCNC decays of the baryon

    L. Mott🇺🇸 · W. Roberts🇺🇸

    Branching ratios, lepton forward-backward asymmetries, and lepton polarization asymmetries for the flavor-changing neutral current (FCNC) dileptonic decays of the baryon to the ground state and a number of excited state baryons are calculated using form factors extracted using wave functions from a constituent quark model. The SM branching ratios for the transition to the ground state calculated using these quark model form factors are consistent with the recent measurement reported by the LHCb collaboration. It is shown that the lepton polarization asymmetries are largely insensitive to the transition form factors and, therefore, to the effects of QCD in the nonperturbative regime. These observables can therefore provide somewhat model independent ways of extracting various combinations of the Wilson coefficients.

    Comments:
    44 pages, 34 figures, To be submitted to IJMPA. arXiv admin note: substantial text overlap with arXiv:1108.6129
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1506.04106 [pdf]
    Int.J.Mod.Phys.A(2015)·19 citations
  6. 06

    [Submitted on 12 Jun 2015]

    Laser-Nucleus Interactions: The Quasiadiabatic Regime

    Adriana Pálffy · Oliver Buss · Axel Hoefer · Hans A. Weidenmüller

    The interaction between nuclei and a strong zeptosecond laser pulse with coherent MeV photons is investigated theoretically. We provide a first semi-quantitative study of the quasiadiabatic regime where the photon absorption rate is comparable to the nuclear equilibration rate. In that regime, multiple photon absorption leads to the formation of a compound nucleus in the so-far unexplored regime of excitation energies several hundred MeV above the yrast line. The temporal dynamics of the process is investigated by means of a set of master equations that account for dipole absorption, stimulated dipole emission, neutron decay and induced fission in a chain of nuclei. That set is solved numerically by means of state-of-the-art matrix exponential methods also used in nuclear fuel burnup and radioactivity transport calculations. Our quantitative estimates predict the excitation path and range of nuclei reached by neutron decay and provide relevant information for the layout of future experiments.

    Comments:
    14 pages, 9 figures; v2 minor modifications in text, results unchanged
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1506.04127 [pdf]
    PRC(2015)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE