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Nuclear Theory·nucl-th

Wednesday·January 6, 2016

8 papers—4 primary·4 cross-listed

All8Primary4Cross-lists4
  1. 01

    [Submitted on 4 Jan 2016]

    Pairing Nambu-Goldstone Modes within Nuclear Density Functional Theory

    Nobuo Hinohara · Witold Nazarewicz

    We show that the Nambu-Goldstone formalism of the broken gauge symmetry in the presence of the pairing condensate offers a quantitative description of the binding-energy differences of open-shell superfluid nuclei. We conclude that the pairing-rotational moments of inertia are excellent pairing indicators, which are free from ambiguities attributed to odd-mass systems. We offer a new, unified interpretation of the binding-energy differences traditionally viewed in the shell model picture as signatures of the valence nucleon properties. We present the first systematic analysis of the off-diagonal pairing-rotational moments of inertia and demonstrate the mixing of the neutron and proton pairing-rotational modes in the ground states of even-even nuclei. Finally, we discuss the importance of mass measurements of neutron-rich nuclei for constraining the pairing energy density functional.

    Comments:
    6 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1601.00677 [pdf]
    PRL(2016)·34 citations
  2. 02

    [Submitted on 5 Jan 2016]

    Jet Fragmentation via Recombination of Parton Showers

    Kyong Chol Han🇺🇸 · Rainer J. Fries🇺🇸 · Che Ming Ko🇺🇸

    We propose to model hadronization of parton showers in QCD jets through a hybrid approach involving quark recombination and string fragmentation. This is achieved by allowing gluons at the end of the perturbative shower evolution to undergo a non-perturbative splitting into quark and antiquark pairs, then applying a Monte-Carlo version of instantaneous quark recombination, and finally subjecting remnant quarks (those which have not found a recombination partner) to Lund string fragmentation. When applied to parton showers from the PYTHIA Monte Carlo event generator, the final hadron spectra from our calculation compare quite well to PYTHIA jets that have been hadronized with the default Lund string fragmentation. Our new approach opens up the possibility to generalize hadronization to jets embedded in a quark gluon plasma.

    Comments:
    10 Pages, 8 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1601.00708 [pdf]
    PRC(2016)·70 citations
  3. 03

    [Submitted on 5 Jan 2016]

    Effects of EoS in viscous hydro+cascade model for the RHIC Beam Energy Scan

    Iu. Karpenko🇮🇹 · M. Bleicher🇩🇪 · P. Huovinen🇩🇪 · H. Petersen🇩🇪

    A state-of-the-art 3+1 dimensional cascade + viscous hydro + cascade model vHLLE+UrQMD has been applied to heavy ion collisions in RHIC Beam Energy Scan range GeV. Based on comparison to available experimental data it was estimated that an effective value of shear viscosity over entropy density ratio in hydrodynamic stage has to decrease from to as collision energy increases from to GeV, and to stay at for GeV. In this work we show how an equation of state with first order phase transition affects the hydrodynamic evolution at those collision energies and changes the results of the model as compared to "default scenario" with a crossover type EoS from chiral model.

    Comments:
    4 pages and 3 figures. Proceedings of Quark Matter 2015, Kobe, Japan
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1601.00800 [pdf]
    NPA(2016)·7 citations
  4. 04

    [Submitted on 5 Jan 2016]

    Anisotropic parton escape is the dominant source of azimuthal anisotropy in transport models

    Liang He · Terrence Edmonds · Zi-Wei Lin · Feng Liu · Denes Molnar · Fuqiang Wang

    We trace the development of elliptic anisotropy (v2) via parton-parton collision history in two transport models. The parton v2 is studied as a function of the number of collisions of each parton in Au+Au and d+Au collisions at sNN =200 GeV. It is found that the majority of v2 comes from the anisotropic escape probability of partons, with no fundamental difference at low and high transverse momenta. The contribution to v2 from hydrodynamic-type collective flow is found to be small. Only when the parton-parton cross-section is set unrealistically large does this contribution start to take over. Our findings challenge the current paradigm emerged from hydrodynamic comparisons to anisotropy data.

    Comments:
    This paper has been withdrawn by the author due to duplication with arXiv:1502.05572
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1601.00878 [pdf]
    Physics Letters B (2016), pp. 506-510

Affiliations

first authorsco-authorsvia INSPIRE