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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

Affiliations

first authorsco-authorsvia INSPIRE