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Nuclear Theory·nucl-th

Friday·February 15, 2019

11 papers—6 primary·5 cross-listed

All11Primary6Cross-lists5
  1. 01

    [Submitted on 13 Feb 2019]

    Equation of state at finite densities for QCD matter in nuclear collisions

    Akihiko Monnai🇯🇵 · Björn Schenke🇺🇸 · Chun Shen🇺🇸

    We construct the QCD equation of state at finite chemical potentials including net baryon, electric charge, and strangeness, based on the conserved charge susceptibilities determined from lattice QCD simulations and the equation of state of the hadron resonance gas model. For the application to relativistic heavy ion collisions we consider the situation of strangeness neutrality and matter with a fixed electric charge-to-baryon ratio, resembling that of heavy nuclei. The importance of finite electric charge and strangeness chemical potentials for particle production in heavy ion collisions is demonstrated using hydrodynamic simulations.

    Comments:
    14 pages, 9 figures; revised version to appear in Physical Review C
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1902.05095 [pdf]
    PRC(2019)·180 citations
  2. 02

    [Submitted on 14 Feb 2019]

    Coherent dibaryons

    Boris Kostenko🇷🇺

    There are encouraging evidences for registration of excitations of quark oscillator levels in compressed 2-nucleon systems, which were hidden in two independently published experimental works for many years. Data obtained by EVA collaboration can be considered as the third possible confirmation of this conjecture. Moreover, they drop hints about existence of coherent dibaryons which may be interpreted as usual or generalized coherent states of the oscillator. These data may also be an explicit example of a physical process described by Landau and Peierls in their reasoning concerning the energy-time uncertainty relation. Two models of the coherent dibaryon creation are formulated. Phase transitions of baryon matter in few-nucleon systems are discussed.

    Comments:
    Reported at Baldin ISHEPP XXIV, September 19, 2018
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1902.05252 [pdf]
    1 citation
  3. 03

    [Submitted on 14 Feb 2019]

    Photoproduction in a Reggeized model

    Ai-Chao Wang🇨🇳 · Fei Huang🇨🇳 · Wen-Ling Wang🇨🇳 · Guang-Xiong Peng🇨🇳

    The high-precision differential cross-section data for the reaction are reanalyzed within a Regge-inspired effective Lagrangian approach. The model adopts Regge phenomenology to constrain the -channel contributions from the , , and exchanges. A minimal number of resonances in the channel are introduced in constructing the reaction amplitudes in order to describe the data. It is shown that the differential cross-section data for can be satisfactorily described by introducing the only resonance in the channel, which is quite different from our earlier work performed in an effective Lagrangian approach [A. C. Wang {\it et al.}, Phys. Rev. C 96, 035206 (2017)], where the amplitudes are computed by evaluating Feynman diagrams and it is found that introducing at least one additional resonance apart from the is indispensable for reproducing the data. The roles of individual contributions from meson and baryon exchanges on the angular distributions are found to be highly model dependent. The extracted mass of turns out to be well determined, independent of how the -channel amplitudes are constructed, whereas the width does not.

    Comments:
    10 pages, 5 figures, version published in PRC
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1902.05267 [pdf]
    PRC(2020)·11 citations
  4. 04

    [Submitted on 14 Feb 2019]

    Triplet structure of nuclear scissors mode

    E. B. Balbutsev🇷🇺 · I. V. Molodtsova🇷🇺 · A. V. Sushkov · N. Yu. Shirikova · P. Schuck🇫🇷

    The fine structure of the scissors mode is investigated within the Time Dependent Hartree-Fock-Bogoliubov (TDHFB) approach. The solution of TDHFB equations by the Wigner Function Moments (WFM) method predicts a splitting of the scissors mode into three intermingled branches. Together with the conventional scissors mode two new modes arise due to spin degrees of freedom. They generate significant strength below the conventional energy range. The results of calculations of scissors resonances in Rare Earths and Actinides by WFM and QPNM methods are compared with experimental data. A remarkable coherence of both methods together with experimental data is observed.

    Comments:
    24 pages, 11 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1902.05275 [pdf]
    Phys.Atom.Nucl.(2020)·4 citations
  5. 05

    [Submitted on 14 Feb 2019]

    Approximate self-energy for Fermi systems with large s-wave scattering length: a step towards density functional theory

    Antoine Boulet🇫🇷 · Denis Lacroix🇫🇷

    In the present work, we start from a minimal Hamiltonian for Fermi systems where the s-wave scattering is the only low energy constant at play. Many-Body Perturbative approach that is usually valid at rather low density is first discussed. We then use the resummation technique with the ladder approximation to obtain compact expressions for both the energy and/or the on-shell self-energy in infinite spin-degenerated systems. Diagrammatic resummation technique has the advantage in general to be predictive in a region of density larger compared to many-body perturbation theory. It also leads to non-diverging limit as . Still, the obtained expressions are rather complex functional of the Fermi momentum . We introduce the full phase-space average or the partial phase-space methods respectively applied to the energy or to the self-energy to simplify their dependences in terms of while keeping the correct limit at low density and the non-diverging property at large . Quasi-particle properties of Fermi system in various regime of density and scattering length are then illustrated. Our conclusion is that such simplified expressions where the direct link is made with the low energy constant without fine-tuning can provide a clear guidance to obtain density functional theory beyond the perturbative regime. However, quasi-particle properties close or near unitary cannot be reproduced unless this limit is explicitly used as a constraint. We finally discuss how such approximate treatment of quasi-particle can guide the development of density functional theory for strongly interacting Fermi systems.

    Subjects:
    Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas)
    arXiv:
    1902.05477 [pdf]
    J.Phys.G(2019)·10 citations
  6. 06

    [Submitted on 14 Feb 2019]

    Bayesian modeling of the nuclear equation of state for neutron star tidal deformabilities and GW170817

    Y. Lim🇺🇸 · J. W. Holt🇺🇸

    We present predictions for neutron star tidal deformabilities obtained from a Bayesian analysis of the nuclear equation of state, assuming a minimal model at high-density that neglects the possibility of phase transitions. The Bayesian posterior probability distribution is constructed from priors obtained from microscopic many-body theory based on realistic two- and three-body nuclear forces, while the likelihood functions incorporate empirical information about the equation of state from nuclear experiments. The neutron star crust equation of state is constructed from the liquid drop model, and the core-crust transition density is found by comparing the energy per baryon in inhomogeneous matter and uniform nuclear matter. From the cold -equilibrated neutron star equation of state, we then compute neutron star tidal deformabilities as well as the mass-radius relationship. Finally, we investigate correlations between the neutron star tidal deformability and properties of finite nuclei.

    Comments:
    15 pages, 17 figures. Invited contribution to the EPJA Topical Issue "First joint gravitational wave and electromagnetic observations: Implications for nuclear and particle physics"
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    1902.05502 [pdf]
    EPJA(2019)·111 citations

Affiliations

first authorsco-authorsvia INSPIRE