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Nuclear Theory·nucl-th

Thursday·March 31, 2016

12 papers—5 primary·7 cross-listed

All12Primary5Cross-lists7
  1. 01

    [Submitted on 30 Mar 2016]

    Phase transition of strongly interacting matter with a chemical potential dependent Polyakov loop potential

    Guo-yun Shao🇨🇳 · Zhan-duo Tang🇨🇳 · Massimo Di Toro🇮🇹 · Maria Colonna🇮🇹 · Xue-yan Gao🇨🇳 · Ning Gao🇨🇳

    We construct a hadron-quark two-phase model based on the Walecka-quantum hadrodynamics and the improved Polyakov-Nambu--Jona-Lasinio model with an explicit chemical potential dependence of Polyakov-loop potential (PNJL model). With respect to the original PNJL model, the confined-deconfined phase transition is largely affected at low temperature and large chemical potential. Using the two-phase model, we investigate the equilibrium transition between hadronic and quark matter at finite chemical potentials and temperatures. The numerical results show that the transition boundaries from nuclear to quark matter move towards smaller chemical potential (lower density) when the -dependent Polyakov loop potential is taken. In particular, for charge asymmetric matter, we compute the local asymmetry of quarks in the hadron-quark coexisting phase, and analyse the isospin-relevant observables possibly measurable in heavy-ion collision (HIC) experiments. In general new HIC data on the location and properties of the mixed phase would bring relevant information on the expected chemical potential dependence of the Polyakov Loop contribution.

    Comments:
    11 pages, 10 figures, 1 Table, accepted for publication by Phys. Rev. D
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1603.09033 [pdf]
    PRD(2016)·24 citations
  2. 02

    [Submitted on 30 Mar 2016]

    Multiplicity dependent and non-binomial efficiency corrections for particle number cumulants

    Adam Bzdak🇵🇱 · Romain Holzmann🇩🇪 · Volker Koch🇺🇸

    In this note we extend previous work on efficiency corrections for cumulant measurements [1,2]. We will discuss the limitations of the methods presented in these papers. Specifically we will consider multiplicity dependent efficiencies as well as a non-binomial efficiency distributions. We will discuss the most simple and straightforward methods to implement those corrections.

    Comments:
    11 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1603.09057 [pdf]
    PRC(2016)·55 citations
  3. 03

    [Submitted on 30 Mar 2016]

    Rapidity distribution of protons from the potential version of UrQMD model and the traditional coalescence afterburner

    Qingfeng Li🇨🇳 · Yongjia wang🇨🇳 · Xiaobao Wang🇨🇳 · Caiwan Shen🇨🇳

    Rapidity distributions of both E895 proton data at AGS energies and NA49 net proton data at SPS energies can be described reasonably well with a potential version of the UrQMD in which mean-field potentials for both pre-formed hadrons and confined baryons are considered, with the help of a traditional coalescence afterburner in which one parameter set for both relative distance and relative momentum , (3.8 fm, 0.3 GeVc), is used. Because of the large cancellation between the expansion in and the shrinkage in through the Lorentz transformation, the relativistic effect in clusters has little effect on the rapidity distribution of free (net) protons. Using a Woods-Saxon-like function instead of a pure logarithmic function as seen by FOPI collaboration at SIS energies, one can fit well both the data at SIS energies and the UrQMD calculation results at AGS and SPS energies. Further, it is found that for central Au+Au or Pb+Pb collisions at top SIS, SPS and RHIC energies, the proton fractions in clusters are about 33, 10, and 0.7, respectively.

    Comments:
    9 pages, 3 figures. arXiv admin note: substantial text overlap with arXiv:1507.06033
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1603.09081 [pdf]
    SCPMA(2016)·20 citations
  4. 04

    [Submitted on 30 Mar 2016]

    Helium-3 production from Pb+Pb collisions at SPS energies with the UrQMD model and the traditional coalescence afterburner

    Qingfeng Li🇨🇳 · Yongjia Wang🇨🇳 · Xiaobao Wang🇨🇳 · Caiwan Shen🇨🇳

    A potential version of the UrQMD (UrQMD/M) transport model and a traditional coalescence model are combined to calculate the production of He fragments in central Pb+Pb collisions at SPS energies 20-80 GeV/nucleon. It is found that the Lorentz transformation in the afterburner influences visibly the He yield and should be considered in calculations. The rapidity distribution of He multiplicities (including the concave shape) can be described well with UrQMD/M when it stops during t=10025 fm and the coalescence afterburner with one parameter set of (,)=(3.8 fm, 0.3 GeVc) is taken into use afterwards.

    Comments:
    9 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1603.09084 [pdf]
    SCPMA(2016)·16 citations
  5. 05

    [Submitted on 30 Mar 2016]

    An explanation of the elliptic flow difference between proton and anti-proton from the UrQMD model with hadron potentials

    Qingfeng Li🇨🇳 · Yongjia Wang🇨🇳 · Xiaobao Wang🇨🇳 · Caiwan Shen🇨🇳

    The time evolution of both proton and anti-proton flows from Au+Au collisions at =7.7 GeV are examined by using both pure cascade and mean-field potential versions of the UrQMD model. Due to a stronger repulsion at the early stage introduced by the repulsive potentials and hence much less annihilation probabilities, anti-protons are frozen out earlier with smaller values. Therefore, the experimental data of anti-proton as well as the flow difference between proton and anti-proton can be reasonably described with the potential version of UrQMD.

    Comments:
    14 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1603.09087 [pdf]
    SCPMA(2016)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE