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Nuclear Theory·nucl-th

Thursday·July 19, 2018

10 papers—6 primary·4 cross-listed

All10Primary6Cross-lists4
  1. 01

    [Submitted on 17 Jul 2018]

    Nuclear and neutron matter equations of state from high-quality potentials up to fifth order of the chiral expansion

    F. Sammarruca🇺🇸 · L. E. Marcucci🇮🇹 · L. Coraggio🇮🇹 · J. W. Holt🇺🇸 · N. Itaco🇮🇹 · R. Machleidt🇺🇸

    We present predictions for the equation of state of symmetric nuclear and pure neutron matter based on recent high-quality nucleon-nucleon potentials from leading order to fifth order in the chiral expansion. We include as well the next-to-next-to-leading order (N2LO) chiral three-nucleon force whose low-energy constants cD and cE are fitted to the binding energies of 3H and 3He as well as the \b{eta}-decay lifetime of 3H. The ground state energy per particle is computed in the particle- particle ladder approximation up to a few times saturation density. Due to the soft character of the interactions, uncertainties due to the convergence in many-body perturbation theory are small. We find that nuclear matter saturation is reproduced quantitatively at N3LO and N4LO, and therefore we encourage the application of these interactions in finite nuclei, where the description of ground- state energies and charge radii of medium-mass nuclei may be improved.

    Comments:
    11 pages, 12 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1807.06640 [pdf]
    37 citations
  2. 02

    [Submitted on 18 Jul 2018]

    Effects of the initialization of nucleon momentum in heavy-ion collisions at medium energies

    Zu-Xing Yang🇨🇳 · Xiao-Hua Fan🇨🇳 · Gao-Chan Yong🇨🇳 · Wei Zuo🇨🇳

    Based on the Isospin-dependent transport model Boltzmann-Uehling-Uhlenbeck (IBUU), effects of the difference of the high momentum tails (HMTs) of nucleon momentum distribution in colliding nuclei on some isospin-sensitive observables are studied in the reactions at incident beam energy of 400 MeV/nucleon. It is found that the nucleon transverse and elliptic flows, the free neutron to proton ratio at low momenta are all less sensitive to the specific form of the HMT, while the free neutron to proton ratio at high momenta and the yields of and as well as the ratio around the Coulomb peak are sensitive to the specific form of the HMT. Combining the present studies with the experimental measurements at rare-isotope reaction facilities worldwide, one may get more insights into the nuclear short-range correlations in heavy nuclei or nuclear matter.

    Comments:
    5 pages, 8 figures, accepted by PRC
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1807.06727 [pdf]
    PRC(2018)·14 citations
  3. 03

    [Submitted on 18 Jul 2018]

    From in-Medium Color Forces to Transport Properties of QGP

    Shuai Y.F. Liu🇺🇸 · Ralf Rapp🇺🇸

    A thermodynamic quantum many-body -matrix approach is employed to study the spectral and transport properties of the quark-gluon plasma at moderate temperatures where nonperturbative effects are essential. For the partonic two-body interaction we utilize a QCD-inspired Hamiltonian whose color forces are motivated by the heavy-quark (HQ) limit including remnants of the confining force, and augmented by relativistic corrections. We solve the in-medium parton propagators and -matrices selfconsistently and resum the skeleton diagrams for the equation of state (EoS) to all orders thereby accounting for the dynamical formation of two-body bound states. Two types solutions for the in-medium potential are found in when fitting to lattice-QCD data for the EoS, HQ free energy and quarkonium correlators: a weakly-coupled scenario (WCS) with a (real part of the) potential close to the free energy, resulting in moderately broadened spectral functions and weak bound states near , and a strongly-coupled scenario (SCS), with a much stronger potential which produces large imaginary parts ("melting" the parton spectral functions) and generates strong bound states near . We calculate pertinent transport coefficients (specific shear viscosity and HQ diffusion coefficient) and argue that their constraints from heavy-ion phenomenology unambiguously favor the strongly-coupled scenario.

    Comments:
    4 pages, 2 figures, Proceedings for Quark Matter 2018
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex)
    arXiv:
    1807.06739 [pdf]
    NPA(2019)·2 citations
  4. 04

    [Submitted on 18 Jul 2018]

    A New Model for Calculating the Ground and Excited States Masses Spectra of Doubly Heavy Baryons

    Neda Mohajery🇮🇷 · Nasrin Salehi🇮🇷 · Hassan Hassanabadi🇮🇷

    In this study, since the doubly heavy baryons masses are experimentally unknown (except and ), we present the ground state masses and the positive and negative parity excited state masses of doubly heavy baryons. For this purpose, we have solved the six-dimensional hyperradial Schrödinger equation analytically for three particles under the hypercentral potential by using the ansatz approach. In this paper the hypercentral potential is regarded as a combination of the color Coulomb plus linear confining term and the six-dimensional harmonic oscillator potential. We also added the first order correction and the spin-dependent part contains three types of interaction terms (the spin-spin term, spin-orbit term and tensor term) to the hypercentral potential. Our obtained masses for the radial excited states and orbital excited states of , , , , and systems are compared with other theoretical reports, which could be a beneficial tool for the interpretation of experimentally unknown doubly heavy baryons spectrum.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1807.06800 [pdf]
    Adv.High Energy Phys.(2018)·12 citations
  5. 05

    [Submitted on 18 Jul 2018]

    Taylor approximation to treat nonlocality in scattering processes

    N. J. Upadhyay · A. Bhagwat

    Study of scattering process in the nonlocal interaction framework leads to an integro-differential equation. The purpose of the present work is to develop an efficient approach to solve this integro-differential equation with high degree of precision. The method developed here employs Taylor approximation for the radial wave function which converts the integro-differential equation in to a readily solvable second-order homogeneous differential equation. This scheme is found to be computationally efficient by a factor of 10 when compared to the iterative scheme developed in J.~Phys.~G~Nucl.~Part.~Phys.~{\bf 45},~015106~(2018). The calculated observables for neutron scattering off Mg, Ca, Mo and Pb with energies up to 10 MeV are found to be within at most 8 of those obtained with the iterative scheme. Further, we propose an improvement over the Taylor scheme that brings the observables so close to the results obtained by iterative scheme that they are visually indistinguishable. This is achieved without any appreciable change in the run time.

    Comments:
    9 pages, 9 figures, accepted in Physical Review C
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1807.06806 [pdf]
    PRC(2018)·7 citations
  6. 06

    [Submitted on 18 Jul 2018]

    Nuclear Statistical Equilibrium Equation of State for Core Collapse

    Ad. R. Raduta (IFIN-HH Bucharest)🇷🇴 · F. Gulminelli (LPC Caen)🇫🇷

    Extensive calculations of properties of supernova matter are presented, using the extended Nuclear Statistical Equilibrium model of PRC92 055803 (2015) based on a statistical distribution of Wigner-Seitz cells modeled using realistic nuclear mass and level density tables, complemented with a non-relativistic Skyrme functional for unbound particles and beyond drip-line nuclei. Both thermodynamic quantities and matter composition are examined as a function of baryonic density, temperature, and proton fraction, within a large domain adapted for applications in supernova simulations. The results are also provided in the form of a table, with grid mesh and format compatible with the CompOSE platform [http://compose.obspm.fr/] for direct use in supernova simulations. Detailed comparisons are also presented with other existing databases, all based on relativistic mean-field functionals, and the differences between the different models are outlined. We show that the strongest impact on the predictions is due to the different hypotheses used to define the cluster functional and its modifications due to the presence of a nuclear medium.

    Comments:
    33 pages, 8 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1807.06871 [pdf]
    NPA(2019)·43 citations

Affiliations

first authorsco-authorsvia INSPIRE