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Nuclear Theory·nucl-th

Thursday·January 23, 2020

6 papers—4 primary·2 cross-listed

All6Primary4Cross-lists2
  1. 01

    [Submitted on 22 Jan 2020]

    Collective inertial masses in nuclear reactions

    Kai Wen · Takashi Nakatsukasa

    Towards the microscopic theoretical description for large amplitude collective dynamics, we calculate the coefficients of inertial masses for low-energy nuclear reactions. Under the scheme of energy density functional, we apply the adiabatic self-consistent collective coordinate (ASCC) method, as well as the Inglis' cranking formula to calculate the inertias for the translational and the relative motions, in addition to those for the rotational motion. Taking the scattering between two particles as an example, we investigate the impact of the time-odd components of the mean-field potential on the collective inertial masses. The ASCC method asymptotically reproduces the exact masses for both the relative and translational motions. On the other hand, the cranking formula fails to do so when the time-odd components exist.

    Comments:
    8 pages, 9 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2001.07842 [pdf]
    Front.in Phys.(2020)·2 citations
  2. 02

    [Submitted on 22 Jan 2020]

    Traces of non-equilibrium effects, initial condition, bulk dynamics and elementary collisions in the charm observables

    Taesoo Song🇩🇪 · Pierre Moreau🇺🇸 · Yingru Xu🇺🇸 · Vitalii Ozvenchuk🇵🇱 · Elena Bratkovskaya🇩🇪 · Jorg Aichelin🇫🇷 · Steffen A. Bass🇺🇸 · Pol Bernard Gossiaux🇫🇷 · Marlene Nahrgang🇫🇷

    We study how heavy quark dynamics is affected by the nature of the bulk evolution of the QCD matter, the initial condition of the system, and the treatment of elementary interactions between heavy quarks and the surrounding medium. For the same initial condition and the same QGP expansion scenario we discuss the consequences of the assumption of a local equilibrium by comparing the consequences for the nuclear modification factor and the elliptic flows of charm quarks. For this purpose we employ the parton-hadron-string dynamics (PHSD), which is an off-shell microscopic transport approach, as well as the linearized-Boltzmann (LB) scheme obtained by coarse graining the PHSD bulk and assuming local equilibrium for the interactions of the charm quarks with the bulk. The of charm quarks stemming from the later LB approach is also compared to a genuine fluid dynamics evolution initiated by the coarse grained PHSD, which allows to further assess the consequences of reducing the full n-body dynamics. We then proceed to a systematic comparison of PHSD with MC@HQ, another transport model for heavy flavors which also relies on LB approach. In particular, we investigate the consequences for the nuclear modification factor of charm quarks if we vary separately the initial heavy quark distribution function in matter, the expansion dynamics of the QGP and the elementary interactions of heavy quarks of these models. We find that the results for both models vary significantly depending on the details of the calculation. However, both models achieve very similar predictions for key heavy quark observables for certain combinations of initial condition, bulk evolution and interactions. We conclude that this ambiguity limits our ability to determine the different properties of the system based on the current set of observables.

    Comments:
    18 pages, 10 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2001.07951 [pdf]
    PRC(2020)·16 citations
  3. 03

    [Submitted on 22 Jan 2020]

    Equivalence between first-order causal and stable hydrodynamics and Israel-Stewart theory for boost-invariant systems with a constant relaxation time

    Arpan Das🇵🇱 · Wojciech Florkowski🇵🇱 · Jorge Noronha🇺🇸 · Radoslaw Ryblewski🇵🇱

    We show that the recently formulated causal and stable first-order hydrodynamics has the same dynamics as Israel-Stewart theory for boost-invariant, Bjorken expanding systems with a conformal equation of state and a regulating sector determined by a constant relaxation time. In this case, the general solution of the new first-order formulation can be determined analytically.

    Comments:
    significant improvement with respect to the previous manuscript, a new author added, 5 pages
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2001.07983 [pdf]
    PLB(2020)·27 citations
  4. 04

    [Submitted on 22 Jan 2020]

    Lee-Yang-inspired energy-density functional including contributions from -wave scattering

    Jeremy Bonnard🇬🇧 · Marcella Grasso🇫🇷 · Denis Lacroix🇫🇷

    The ELYO functional proposed in [M. Grasso, D. Lacroix, and C. J. Yang, Phys. Rev. C \textbf{95}, 054327 (2017)] belongs to the family of energy-density functionals (EDFs) inspired by effective-field theories (EFTs) and constrained by \textit{ab--initio} pseudo-data. We present here an extension of this EDF which also accounts for the first -wave term appearing in the low-density expansion from which it derives. It is shown that this enrichment of the ansatz on which the functional is based leads to a significant improvement of the description of neutronic systems, especially in regimes besides the pseudo--data set employed to adjust the parameters. As an illustrative application, the mass-radius relation of neutron stars is considered. In contrast to its initial version, the new functional predicts values which are qualitatively consistent with recent observations.

    Comments:
    10 pages, 8 figures, 2 tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2001.08082 [pdf]
    PRC(2020)·12 citations
  5. 05

    [Submitted on 22 Jan 2020] (cross-list from hep-ph)

    Relativistic hypernuclear compact stars with calibrated equations of state

    M. Fortin🇵🇱 · A. R. Raduta🇷🇴 · S. Avancini🇧🇷 · C. Providência🇵🇹

    Within the covariant density functional theory of hypernuclear matter we build a series of equations of state for hypernuclear compact stars, by calibrating the coupling constants of the -hyperon to the experimental binding energy of the single- hypernuclei C and Be. Coupling constants of the -hyperon to nucleons have been calibrated on a vast collection of experimental data on single -hypernuclei and we employ those values. Uncertainties on the couplings of the -hyperon to nuclear matter, due to lack of experimental data, are accounted for by allowing for a wide variation of the well depth of at rest in symmetric saturated nuclear matter. To account for uncertainties in the nucleonic sector at densities much larger than the saturation density, a rich collection of parametrizations is employed, some of them in agreement with existing constraints from nuclear physics and astrophysics. Neutron star properties are investigated with all these calibrated equations of state. The effects of the presence of hyperons on the radius, on the tidal deformability, on the moment of inertia, and on the nucleonic direct Urca process are discussed. The sensitivity of the hyperonic direct Urca processes to uncertainties in the nucleonic and hyperonic sectors is also addressed. It is shown that the relative variations of the radius, tidal deformability and moment of inertia from the values that characterize purely nucleonic stars are linearly correlated with the strangeness fraction. The maximum radius deviation, obtained for most massive neutron stars, is . The reduction of the maximum mass, triggered by nucleation of strangeness, is estimated at , out of which 5\% comes from insufficient information on the -hyperon interactions.

    Comments:
    Open access. Supplemental Material available at https://journals.aps.org/prd/abstract/10.1103/PhysRevD.101.034017
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    2001.08036 [pdf]
    PRD(2020)·61 citations
  6. 06

    [Submitted on 22 Jan 2020] (cross-list from hep-ph)

    Effects of local event-by-event conservation laws in ultra-relativistic heavy ion collisions at the particlization

    Dmytro Oliinychenko🇺🇸 · Shuzhe Shi🇨🇦 · Volker Koch🇺🇸

    Many simulations of relativistic heavy ion collisions involve the switching from relativistic hydrodynamics to kinetic particle transport. This switching entails the sampling of particles from the distribution of energy, momentum and conserved currents provided by hydrodynamics. Usually this sampling ensures the conservation of these quantities only on the average, i.e. the conserved quantities may actually fluctuate among the sampled particle configurations and only their averages over many such configurations agree with their values from hydrodynamics. Here we apply a recently invented method [Oliinychenko, Koch; PRL 123, 18, 182302 (2019)] to ensure conservation laws for each sampled configuration in spatially compact regions (patches) and study their effects: from the well-known (micro-)canonical suppression of means and variances to little studied (micro-)canonical correlations and higher order fluctuations. Most of these effects are sensitive to the patch size. Many of them do not disappear even in the thermodynamic limit, when the patch size goes to infinity. The developed method is essential for particlization of stochastic hydrodynamics. It is useful for studying the chiral magnetic effect, small systems, and in general for fluctuation and correlation observables.

    Comments:
    40 pages, 9 figures, version accepted to Phys. Rev. C
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2001.08176 [pdf]
    PRC(2020)·31 citations

Affiliations

first authorsco-authorsvia INSPIRE