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Nuclear Theory·nucl-th

Friday·January 17, 2020

12 papers—6 primary·6 cross-listed

All12Primary6Cross-lists6
  1. 01

    [Submitted on 16 Jan 2020]

    Can chiral EFT give us satisfaction?

    R. Machleidt🇺🇸 · F. Sammarruca🇺🇸

    We compare nuclear forces derived from chiral effective field theory (EFT) with those obtained from traditional (phenomenological and meson) models. By means of a careful analysis of paralleles and differences, we show that chiral EFT is superior to all earlier approaches in terms of both formal aspects and successful applications in ab initio calculations. However, in spite of the considerable progress made possible by chiral EFT, complete satisfaction cannot be claimed until outstanding problems---the renormalization issue being the most important one---are finally settled.

    Comments:
    23 pages, 21 figures; commissioned for the Topical Issue of The European Physical Journal A - Hadrons and Nuclei entitled "The tower of effective (field) theories and the emergence of nuclear phenomena."
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2001.05615 [pdf]
    EPJA(2020)·32 citations
  2. 02

    [Submitted on 16 Jan 2020]

    An implementation of nuclear time-dependent density-functional theory and its application to the nuclear isovector electric dipole resonance

    Yue Shi · Nobuo Hinohara · Bastian Schuetrumpf

    Following a previous paper [Y. Shi, Phys. Rev. C 98, 014329(2018)], we present an extension of the density-functional theory to allow for dynamic calculations based on the obtained static Hartree-Fock results. We perform extensive benchmark calculations, by comparing the calculated results with that of an existing code Sky3D. To perform linear-response calculations using the TDDFT method, comparisons have been made with the finite-amplitude quasiparticle random-phase approximation (FAM-QRPA) method. We plan to apply the TDDFT method to a systematic description of the IVD resonances in the Zr, Mo, and Ru isotopes. The strengths of IVD resonances are calculated using two complementary methods: TDDFT and FAM-QRPA methods. For the TDDFT results, additional benchmark calculations have been performed using the well-tested code Sky3D. In these three models, the important ingredients which have major influence on the results, such as time-odd potentials, boundary conditions, smoothing procedures, spurious peaks etc., have been carefully examined. The current TDDFT and the Sky3D codes yield almost identical response functions once both codes use the same time-odd mean fields and absorbing boundary conditions. The strengths of the IVD resonances calculated using the TDDFT and FAM-QRPA methods agree reasonably well with the same position of the giant dipole resonance. Upon seeing a reasonable accuracy offered by the implemented code, we perform systematic TDDFT calculations for spherical Zr and Mo isotopes near , where experimental data exist. For neutron-rich Zr, Mo, and Ru isotopes where shape evolution exist we predict the photoabsorption cross sections based on oblate and triaxial minima.

    Comments:
    19 pages, 18 figures, 4 tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2001.05664 [pdf]
    PRC(2020)·9 citations
  3. 03

    [Submitted on 15 Jan 2020]

    Mapping QGP interaction through its temperature dependent degeneracy factor

    Ranjesh Kumar🇮🇳 · Ankit Anand🇮🇳 · Souvik Paul🇮🇳 · Sarthak Satapathy🇮🇳 · Sabyasachi Ghosh🇮🇳

    We have parameterized the degeneracy factor in terms of temperature and using this we have tried to compare and study the LQCD(Lattice Quantum Chromodynamics) data with our data.

    Comments:
    http://sympnp.org/snp2019/. arXiv admin note: text overlap with arXiv:1908.04330
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2001.05880 [pdf]
    DAE Symp.Nucl.Phys.(2019)·0 citations
  5. 05

    [Submitted on 16 Jan 2020]

    The Early Stages of Heavy Ion Collisions

    Francois Gelis🇫🇷

    Heavy ion collisions pose interesting challenges to quantum chromodynamics, because they probe the parton structure of the incoming nuclei at very small longitudinal momentum fractions. Combined with the large size of nuclei, this may lead to the phenomenon of gluon saturation. The Color Glass Condensate is an effective QCD description that aims to cope with such a situation. In this talk, I show how one may study heavy ion collisions in this framework.

    Comments:
    Talk given at Light-Cone 2019
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2001.05901 [pdf]
    PoS(2020)·0 citations
  6. 06

    [Submitted on 16 Jan 2020]

    Quantified limits of the nuclear landscape

    Léo Neufcourt · Yuchen Cao · Samuel A. Giuliani · Witold Nazarewicz · Erik Olsen · Oleg B. Tarasov

    The chart of the nuclides is limited by particle drip lines beyond which nuclear stability to proton or neutron emission is lost. Predicting the range of particle-bound isotopes poses an appreciable challenge for nuclear theory as it involves extreme extrapolations of nuclear masses beyond the regions where experimental information is available. Still, quantified extrapolations are crucial for a variety of applications, including the modeling of stellar nucleosynthesis. We use microscopic nuclear mass models and Bayesian methodology to provide quantified predictions of proton and neutron separation energies as well as Bayesian probabilities of existence throughout the nuclear landscape all the way to the particle drip lines. We apply nuclear density functional theory with several energy density functionals. To account for uncertainties, Bayesian Gaussian processes are trained on the separation-energy residuals for each individual model, and the resulting predictions are combined via Bayesian model averaging. This framework allows to account for systematic and statistical uncertainties and propagate them to extrapolative predictions. We characterize the drip-line regions where the probability that the nucleus is particle-bound decreases from to . In these regions, we provide quantified predictions for one- and two-nucleon separation energies. According to our Bayesian model averaging analysis, 7759 nuclei with have a probability of existence . The extrapolations obtained in this study will be put through stringent tests when new experimental information on exotic nuclei becomes available. In this respect, the quantified landscape of nuclear existence obtained in this study should be viewed as a dynamical prediction that will be fine-tuned when new experimental information and improved global mass models become available.

    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex); Machine Learning (stat.ML)
    arXiv:
    2001.05924 [pdf]
    PRC(2020)·112 citations

Affiliations

first authorsco-authorsvia INSPIRE