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Nuclear Theory·nucl-th

Monday·May 11, 2015

6 papers—5 primary·1 cross-listed

All6Primary5Cross-lists1
  1. 01

    [Submitted on 7 May 2015]

    Modeling of heavy-flavor pair correlations in Au-Au collisions at 200 A GeV at the BNL Relativistic Heavy Ion Collider

    Shanshan Cao🇺🇸 · Guang-You Qin🇨🇳 · Steffen A. Bass🇺🇸

    We study the nuclear modification of angular and momentum correlations between heavy quark pairs in ultrarelativistic heavy-ion collisions. The evolution of heavy quarks inside the thermalized medium is described via a modified Langevin approach that incorporates both elastic and inelastic interactions with the medium constituents. The spacetime evolution of the fireball is obtained from a (2+1)-dimensional viscous hydrodynamics simulation. The hadronization of heavy quarks is performed utilizing a hybrid model of fragmentation and coalescence. Our results show that the nuclear modification of the transverse momentum imbalance of D\bar{D} pairs reflects the total energy loss experienced by the heavy quarks and may help us probe specific regions of the medium. The angular correlation of heavy flavor pairs, especially in the low to intermediate transverse momentum regime, is sensitive to the detailed energy loss mechanism of heavy quarks inside the QGP.

    Comments:
    10 pages, 9 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1505.01869 [pdf]
    PRC(2015)·56 citations
  2. 02

    [Submitted on 8 May 2015]

    The radiative capture reaction rate from to H dibaryon in the imaginary time method

    E. Hikota🇯🇵 · Y. Funaki🇯🇵 · E. Hiyama🇯🇵 · M. Oka🇯🇵

    Radiative capture rates of thermal N states into H dibaryon are calculated in the novel imaginary time method. The H dibaryon is assumed to be a bound state of N with spin , isospin and strangeness . We consider transition to H from N scattering states which mix with . In order to calculate the transition rates, we formulate a coupled-channel imaginary time method by extending the one-channel formula originally proposed by Yabana and Funaki. The imaginary time method allows us to avoid the sum over all the excited thermal initial states, and thus to save computational time significantly. The transition rates are given as a function of temperature and the unknown binding energy of the H dibaryon, which we take as a parameter. It is found that the transition rate is not sensitive to the choices of the H binding energy or the strengths of the channel coupling for temperatures 3 MeV or higher.

    Comments:
    10 pages, 14 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1505.01912 [pdf]
    PRC(2015)·1 citation
  3. 03

    [Submitted on 8 May 2015]

    Hybrid chiral condensate in the external magnetic field

    Kazuya Nishiyama🇯🇵 · Shintaro Karasawa🇯🇵 · Toshitaka Tatsumi🇯🇵

    We study the phase diagram of the Nambu-Jona-Lasinio model in the external magnetic field within the mean-field approximation, taking into account the inhomogeneous chiral condensate. It is shown that there appears a new type of the chiral condensate, endowed with two features of real kink crystal and dual chiral density wave, in the magnetic field. We also show that there are first order phase transitions between different inhomogeneous phases in the presence of magnetic field.

    Comments:
    14 pages, 24 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1505.01928 [pdf]
    PRD(2015)·33 citations
  4. 04

    [Submitted on 8 May 2015]

    Non-resonant kaon pair production and medium effects in proton-nucleus collisions

    E. Ya. Paryev🇷🇺 · M. Hartmann🇩🇪 · Yu. T. Kiselev🇷🇺

    We study the non-resonant (non-) production of pairs by protons of 2.83 GeV kinetic energy on C, Cu, Ag, and Au targets within the collision model, based on the nuclear spectral function, for incoherent primary proton--nucleon and secondary pion--nucleon creation processes. The model takes into account the initial proton and final kaon absorption, target nucleon binding and Fermi motion as well as nuclear mean-field potential effects on these processes. We calculate the antikaon momentum dependences of the exclusive absolute and relative pair yields in the acceptance window of the ANKE magnetic spectrometer, used in a recent experiment performed at COSY, within the different scenarios for the antikaon-nucleus optical potential. We demonstrate that the above observables are strongly sensitive to this potential. Therefore, they can be useful to help determine the optical potential from the direct comparison of the results of our calculations with the data from the respective ANKE-at-COSY experiment. We also show that the pion--nucleon production channels dominate in the low-momentum , production in the considered kinematics and, hence, they have to be accounted for in the analysis of these data.

    Comments:
    19 pages
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1505.01992 [pdf]
    J.Phys.G(2015)·9 citations
  5. 05

    [Submitted on 8 May 2015]

    Studying the entropy excess and entropy excess ratio in (105,106,107)Pd within BCS model

    Azam Rahmatinejad · Tayeb Kakavand · Rohallah Razavi

    Pairing correlations and their influence on nuclear properties has been studied within BCS model. Using this theoretical model with inclusion of pairing interaction between nucleons, nuclear level density and entropy of Pd(105,106,107) have been extracted. The results well coincide with the empirical values of the nuclear level densities obtained by Oslo group. Then the entropy excess of Pd107 and Pd105 compared to Pd106 as a function of the temperature has been studied. Also the role of neutron and proton system in entropy excess have been investigated by the using of the entropy excess ratio proposed by Razavi et al. [R. Razavi, A.N. Behkami, S. Mohammadi, and M. Gholami, Phys. Rev. C 86, 047303 (2012)].

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1505.02076 [pdf]
    0 citations

Affiliations

first authorsco-authorsvia INSPIRE