PaperPanorama
FAQ

Nuclear Theory·nucl-th

Thursday·January 19, 2017

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 01

    [Submitted on 18 Jan 2017]

    Theoretical studies on the impact of point defect on the structures of different uranium silicides

    Miao He · Shiyu Du · Heming He · Jiajian Lang · Zhen Liu · Qing Huang · Cheng-Te Lin · Ruifeng Zhang · Dejun Wang

    The structures, point defects and impacts of fission products for U3Si (\b{eta}-U3Si and {\gamma}-U3Si) and USi2 ({\alpha}-USi2 and \b{eta}-USi2) are studied by first-principles calculations. The lattice parameters of U3Si and USi2 are calculated and the stability of different types of point defects is predicted by their formation energies. The results show that silicon vacancies are more prone to be produced than uranium vacancies in \b{eta}-USi2 matrix, while uranium vacancies are the most stable defects of other three types of crystallographic structures. The most favorable sites of fission products (strontium, barium, cerium and neodymium) are determined in this work as well. By calculating incorporation energies of fission products, we demonstrate that the uranium site is the most favored for all the fissions products. Comparing the structural changes influenced by different fission products, it is also found that the highest volume change is caused by barium interstitials. According to the current data, rare earth elements cerium and neodymium are found to be more stable than alkaline earth metals strontium and barium in a given nuclear matrix. Finally, it is also determined that in USi2 crystal lattice fission products tend to be stabilized in uranium substitution sites, while they are likely to form precipitates from the U3Si matrix. It is expected that this work may provide new insight into the mechanism for structural evolutions of silicide nuclear fuels in a reactor.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1701.04962 [pdf]
    0 citations
  2. 02

    [Submitted on 18 Jan 2017]

    Parametric estimate of the relative photon yields from the Glasma and the Quark-Gluon Plasma in heavy-ion collisions

    J. Berges🇩🇪 · K. Reygers🇩🇪 · N. Tanji🇩🇪 · R. Venugopalan🇺🇸

    Recent classical-statistical numerical simulations have established the "bottom-up" thermalization scenario of Baier et al. as the correct weak coupling effective theory for thermalization in ultrarelativistic heavy-ion collisions. We perform a parametric study of photon production in the various stages of this bottom-up framework to ascertain the relative contribution of the off-equilibrium "Glasma" relative to that of a thermalized Quark-Gluon Plasma. Taking into account the constraints imposed by the measured charged hadron multiplicities at RHIC and the LHC, we find that Glasma contributions are important especially for large values of the saturation scale at both energies. These non-equilibrium effects should therefore be taken into account in studies where weak coupling methods are employed to compute photon yields.

    Comments:
    33 pages, 9 figures; version accepted in PRC, title changed
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1701.05064 [pdf]
    PRC(2017)·72 citations
  3. 03

    [Submitted on 18 Jan 2017]

    Effect of pre-equilibrium phase on and of heavy quarks in heavy ion collisions

    Santosh K. Das🇮🇹 · Marco Ruggieri🇨🇳 · Francesco Scardina🇮🇹 · Salvatore Plumari🇮🇹 · Vincenzo Greco🇮🇹

    Heavy quark and have been calculated at RHIC energy considering initial conditions with and without pre-equilibrium phase to highlight the effect of the latter on heavy quark observables. The momentum evolution of the heavy quark has been studied by means of the Boltzmann transport equation. To model the pre-equilibrium phase we have used the KLN initial condition. We have found that the pre-equilibrium phase impacts the of about 20-25 whereas the impact on is very negligible. We have also calculated heavy quark and in the case of initializations with early thermalized quark-gluon plasma. We have checked that the particular form of the initial spectrum is not very important for , the larger energy density being more important. In fact, comparing the results obtained within the two initializations we have found that one can mimic the impact of the pre-equilibrium phase using a early thermalized QGP medium.

    Comments:
    10 pages, 2 figures, Accepted for publication in Journal of Physics G
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1701.05123 [pdf]
    J.Phys.G(2017)·66 citations
  4. 04

    [Submitted on 18 Jan 2017]

    Electromagnetic scaling functions within the Green's Function Monte Carlo approach

    N. Rocco🇪🇸 · L. Alvarez-Ruso🇪🇸 · A. Lovato🇺🇸 · J. Nieves🇪🇸

    We have studied the scaling properties of the electromagnetic response functions of He and C nuclei computed by the Green's Function Monte Carlo approach, retaining only the one-body current contribution. Longitudinal and transverse scaling functions have been obtained in the relativistic and non relativistic cases and compared to experiment for various kinematics. The characteristic asymmetric shape of the scaling function exhibited by data emerges in the calculations in spite of the non relativistic nature of the model. The results are consistent with scaling of zeroth, first and second kinds. Our analysis reveals a direct correspondence between the scaling and the nucleon-density response functions.

    Comments:
    11 pages, 15 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex)
    arXiv:
    1701.05151 [pdf]
    PRC(2017)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE