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Nuclear Theory·nucl-th

Wednesday·February 19, 2020

15 papers—6 primary·9 cross-listed

All15Primary6Cross-lists9
  1. 01

    [Submitted on 17 Feb 2020]

    Fission Fragment Excitation Energy Sharing Beyond Scission

    A. Bulgac

    A simplified, though realistic, model describing two receding and accelerating fission fragments, due to their mutual Coulomb repulsion, shows that fission fragments share excitation energy well after they ceased to exchange nucleons. This mechanism leads to a lower total kinetic energy of the fission fragments, particularly if the pygmy resonances in the fission fragments are excited. Even though the emphasis here is on fission, similar arguments apply to fragments in heavy-ion reactions.

    Comments:
    5 pages, 2 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2002.07244 [pdf]
    PRC(2020)·15 citations
  2. 02

    [Submitted on 18 Feb 2020]

    Critical fluctuations in a dynamically expanding heavy-ion collision

    Masakiyo Kitazawa🇯🇵 · Grégoire Pihan🇫🇷 · Nathan Touroux🇫🇷 · Marcus Bluhm🇫🇷 · Marlene Nahrgang🇫🇷

    For the discovery of the QCD critical point it is crucial to develop dynamical models of the fluctuations of the net-baryon number that can be embedded in simulations of heavy-ion collisions. In this proceeding, we study the dynamical formation of the critical fluctuations of the net-baryon number near the QCD critical point and their survival in the late stages in an expanding system. The stochastic diffusion equation with a non-linear free energy functional is employed for describing the evolution of conserved-charge fluctuations along trajectories in the crossover and first-order transition regions near the QCD critical point.

    Comments:
    4 pages 5 figures, contribution to the proceedings of XXVIIIth International Conference on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2019)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2002.07322 [pdf]
    NPA(2021)·10 citations
  3. 03

    [Submitted on 18 Feb 2020]

    Formation and dynamics of exotic hypernuclei in heavy-ion collisions

    Zhao-Qing Feng🇨🇳

    The dynamics of exotic hypernuclei in heavy-ion collisions has been investigated thoroughly with a microscopic transport model. All possible channels on hyperon (, and ) production near threshold energies are implemented in the transport model. The light complex fragments (Z2) are constructed with the Wigner-function method. The classical phase-space coalescence is used for recognizing heavy nuclear and hyperfragments and the statistical model is taken for describing the decay process. The nuclear fragmentation reactions of the available experimental data from the ALADIN collaboration are well reproduced by the combined approach. It is found that the in-medium potentials of strange particles influence the strangeness production and fragment formation. The hyperfragments are mainly created in the projectile or target-like rapidity region and the yields are reduced about the 3-order magnitude in comparison to the nuclear fragments. The hypernuclear dynamics of HypHI data is well described with the model. The possible experiments for producing the neutron-rich hyperfragments at the high-intensity heavy-ion accelerator facility (HIAF) are discussed.

    Comments:
    8 pages, 8 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2002.07359 [pdf]
    PRC(2020)·18 citations
  4. 04

    [Submitted on 18 Feb 2020]

    Pre-equilibrium Neutron Emission in Fission or Fragmentation

    A. Bulgac

    Fissioning nuclei and fission fragments, nuclear fragments emerging from energetic collisions, or nuclei probed with various external fields can emit one or more pre-equilibrium neutrons, protons, and potentially other heavier nuclear fragments. I describe a formalism which can be used to evaluate the pre-equilibrium neutron emission probabilities and the excitation energies of the remnant fragments.

    Comments:
    8 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2002.07365 [pdf]
    PRC(2020)·5 citations
  5. 05

    [Submitted on 18 Feb 2020]

    Vorticity and Spin Polarization --- A Theoretical Perspective

    Xu-Guang Huang🇨🇳

    We give a theoretical perspective on the vorticity and spin polarization in heavy-ion collisions. We discuss the recent progress in spin hydrodynamics and spin kinetic theory. We also discuss other effects caused by vorticity including the chiral vortical effect and rotation-induced phase transitions.

    Comments:
    V1: 8 pages, 3 figures. For Quark Matter 2019
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2002.07549 [pdf]
    NPA(2021)·50 citations
  6. 06

    [Submitted on 17 Feb 2020]

    Quark cores in extensions of the MIT Bag model

    Salil Joshi🇮🇳 · Sovan Sau🇮🇳 · Soma Sanyal🇮🇳

    Recent observations of massive pulsars having masses of the order of two solar mass pose a new challenge for compact objects such as hybrid stars and neutron stars. Extensions of the bag model and the Nambu-Jona-Lasino model have been used to model these stars to get higher mass stars. Quark matter has been predicted in the cores of these massive stars. In this work we show that an extension of the bag model, with a chemical potential dependent bag parameter can lead to an isentropic phase transition in the core of the neutron star. Our model shows that an EoS having all three quarks , and would lead to massive stars with stable quark matter. We find that the mass of the stars not only depends on the bag constant but also on the mass of the strange quark. The mass - radius ratio which determines the redshift values on the surface, indicates that it is possible to obtain stable self bound strange quark matter stars with reasonable values of the bag pressure which correspond to the recent observations of large mass stars.

    Comments:
    Significantly revised version, results remain the same
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2002.07647 [pdf]
    JHEAp(2021)·21 citations

Affiliations

first authorsco-authorsvia INSPIRE