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Nuclear Theory·nucl-th

Wednesday·August 3, 2016

5 papers—3 primary·2 cross-listed

All5Primary3Cross-lists2
  1. 01

    [Submitted on 1 Aug 2016]

    Contrasting Freezeouts in Large Versus Small Systems

    Sandeep Chatterjee🇮🇳 · Ajay Kumar Dash🇮🇳 · Bedangadas Mohanty🇮🇳

    We study the data on mean hadron yields and contrast the chemical freezeout conditions in p+p, p+Pb and Pb+Pb at the Large Hadron Collider (LHC) energies. We study several schemes for freezeout that mainly differ in the way strangeness is treated: i. strangeness freezes out along with the non-strange hadrons in complete equilibrium (1CFO), ii. strangeness freezes out along with non-strange hadrons with an additional parameter accounting for non-equilibrium production of strangeness (1CFO+), and iii. strangeness freezes out earlier than non-strange hadrons and in thermal equilibrium (2CFO). A comparison of the chisquares of the fits indicate a dependence of the freezeout scheme on the system size. The minimum bias p+p and different centralities of p+Pb and peripheral Pb+Pb data prefer 1CFO with approaching unity as we go from p+p to central p+Pb and peripheral Pb+Pb. On the other hand, the mid-central to central Pb+Pb data prefer 2CFO over 1CFO+. Such system size dependence of freezeout scheme could be an indication of the additional interaction in Pb+Pb over p+Pb and p+p.

    Comments:
    version accepted for publication
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1608.00643 [pdf]
    J.Phys.G(2017)·27 citations
  2. 02

    [Submitted on 2 Aug 2016]

    Unified description of the proton, alpha, cluster decays and spontaneously fissions half- life

    Strachimir Cht. Mavrodiev · M.A. Deliyergiyev

    Some time ago the possibility of classical (without Gamow tunneling) universal description of radioactive nuclei decay was demonstrated. Such possibility is basis on the classical interpretation of Bohmian Psi-field reality in Bohmian-Chetaev mechanics and the hypothesis for the presence of dissipative forces, generated from the Gryzinski translational precession of the charged particles spin, in Langevin- Kramers diffusion mechanism. In this paper is present an unified model of proton, alpha decay, cluster radioactivity and spontaneous fission half-life as explicit function which depends on the total decay energy and kinetic energy, the number of protons and neutrons of daughter product, the number of protons and neutrons of mother nuclei and from a set) unknown digital parameters. The Half- lifes of the 573 nuclei taken from NuDat database together with the recent experimental data from Oganessian provide a basis for discovering the explicit form of the Kramers solution of Langevin type equation in a framework of inverse problem with the help of the Alexandrov dynamic auto-regularization method (FORTRAN program REGN-Dubna). The procedure LCH in program REGN permitts to reduce the number of unknown digital parameters from 137 to 79. The model describes 424 decays quantities with deviation of order one in years power scale.

    Comments:
    25 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1608.00701 [pdf]
    0 citations
  3. 03

    [Submitted on 2 Aug 2016]

    Event simulation based on three-fluid hydrodynamics for collisions at energies available at the Dubna Nuclotron-based Ion Collider Facility and at the Facility for Antiproton and Ion Research in Darmstadt

    P. Batyuk🇷🇺 · D. Blaschke🇵🇱 · M. Bleicher🇩🇪 · Yu. B. Ivanov🇷🇺 · Iu. Karpenko🇺🇦 · S. Merts🇷🇺 · M. Nahrgang🇺🇸 · H. Petersen🇩🇪 · O. Rogachevsky🇷🇺

    We present a new event generator based on the three-fluid hydrodynamics approach for the early stage of the collision, followed by a particlization at the hydrodynamic decoupling surface to join to a microscopic transport model, UrQMD, to account for hadronic final state interactions. We present first results for nuclear collisions of the FAIR/NICA energy scan program (Au+Au collisions, GeV). We address the directed flow of protons and pions as well as the proton rapidity distribution for two model EoS, one with a first order phase transition the other with a crossover type softening at high densities. The new simulation program has the unique feature that it can describe a hadron-to-quark matter transition which proceeds in the baryon stopping regime that is not accessible to previous simulation programs designed for higher energies.

    Comments:
    18 pages, 16 figures, version accepted for publication in Phys. Rev. C, before proof corrections
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1608.00965 [pdf]
    PRC(2016)·58 citations
  4. 04

    [Submitted on 1 Aug 2016] (cross-list from hep-ph)

    Compact stars with strongly coupled quark matter in a strong magnetic field

    D. A. Fogaça🇧🇷 · S. M. Sanches Jr.🇧🇷 · T. F. Motta🇧🇷 · F. S. Navarra🇧🇷

    Some time ago we have derived from the QCD Lagrangian an equation of state (EOS) for the cold quark matter, which can be considered an improved version of the MIT bag model EOS. Compared to the latter, our equation of state reaches higher values of the pressure at comparable baryon densities. This feature is due to perturbative corrections and also to non-perturbative effects. Later we applied this EOS to the study of compact stars, discussing the absolute stability of quark matter and computing the mass-radius relation for self-bound (strange) stars. We found maximum masses of the sequences with more than two solar masses, in agreement with the recent experimental observations. In the present work we include the magnetic field in the equation of state and study how it changes the stability conditions and the mass-radius curves.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1608.00602 [pdf]
    PRC(2016)·9 citations
  5. 05

    [Submitted on 2 Aug 2016] (cross-list from hep-ph)

    Effect of temperature and magnetic field on two-flavor superconducting quark matter

    Tanumoy Mandal🇸🇪 · Prashanth Jaikumar🇺🇸

    We investigate the effect of turning on temperature for the charge neutral phase of two-flavor color superconducting (2SC) dense quark matter in presence of constant external magnetic field. Within the Nambu-Jona-Lasinio model, by tuning the diquark coupling strength, we study the interdependent evolution of the quark Bardeen-Cooper-Schrieffer gap and dynamical mass as functions of temperature and magnetic field. We find that magnetic field GeV ( G) leads to anomalous temperature behavior of the gap in the gapless 2SC phase (moderately strong coupling), reminiscent of previous results in the literature found in the limit of weak coupling without magnetic field. The 2SC gap in the strong coupling regime is abruptly quenched at ultrahigh magnetic field due to the mismatched Fermi surfaces of up and down quarks imposed by charge neutrality and oscillation of the gap due to Landau level quantization. The dynamical quark mass also displays strong oscillation and magnetic catalysis at high magnetic field, although the latter effect is tempered by nonzero temperature. We discuss the implications for newly born compact stars with superconducting quark cores.

    Comments:
    22 pages, 6 figures, 1 table. Matches with the published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1608.00882 [pdf]
    PRD(2016)·15 citations

Affiliations

first authorsco-authorsvia INSPIRE