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Nuclear Theory·nucl-th

Wednesday·August 2, 2017

11 papers—6 primary·5 cross-listed

All11Primary6Cross-lists5
  1. 01

    [Submitted on 31 Jul 2017]

    Relating centrality to impact parameter in nucleus-nucleus collisions

    Sruthy Jyothi Das🇫🇷 · Giuliano Giacalone🇫🇷 · Pierre-Amaury Monard🇫🇷 · Jean-Yves Ollitrault🇫🇷

    In ultrarelativistic heavy-ion experiments, one estimates the centrality of a collision by using a single observable, say , typically given by the transverse energy or the number of tracks observed in a dedicated detector. The correlation between and the impact parameter, , of the collision is then inferred by fitting a specific model of the collision dynamics, such as the Glauber model, to experimental data. The goal of this paper is to assess precisely which information about can be extracted from data without any specific model of the collision. Under the sole assumption that the probability distribution of for a fixed is Gaussian, we show that the probability distribution of the impact parameter in a narrow centrality bin can be accurately reconstructed up to centrality. We apply our methodology to data from the Relativistic Heavy Ion Collider and the Large Hadron Collider. We propose a simple measure of the precision of the centrality determination, which can be used to compare different experiments.

    Comments:
    9 pages, 8 figures; v2, published version: added analysis of CMS data; added fit of STAR data in Fig.6; ancillary file (fit.py) contains a python script which performs the fit of Trento data (trento.dat) on distribution of entropy
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1708.00081 [pdf]
    PRC(2018)·72 citations
  2. 02

    [Submitted on 1 Aug 2017]

    Introduction of the one-body correlation operator in the unitary-model-operator approach

    Takayuki Miyagi · Takashi Abe · Ryoji Okamoto · Takaharu Otsuka

    In the earlier unitary-model-operator approach (UMOA), one-body correlations have been taken into account approximately by the diagonalization of unitary-transformed Hamiltonians in the and space. With this prescription, the dependence of the harmonic-oscillator energy () on calculated observables is not negligible even at larger model spaces. In the present work, we explicitly introduce the one-body correlation operator so that it optimizes the single-particle basis states and then reduces the -dependence. For an actual demonstration, we calculate the energy and radius for the He ground state with the softened nucleon-nucleon () interactions from Argonne v18 (AV18) and chiral effective field theory (EFT) up to the next-to-next-to-next leading order (NLO). As a result, we obtain practically -free results at sufficiently large model spaces. The present results are reasonably close to those by the other ab initio calculations with the same interactions. This methodological development enables us more systematic analysis of calculation results in the UMOA. We also discuss qualitatively the origin of the -dependence on calculated observables in a somewhat simplified way.

    Comments:
    16 pages, 11 figures, published in PRC
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1708.00177 [pdf]
    PRC(2017)·4 citations
  3. 03

    [Submitted on 29 Jul 2017]

    Neutrino-nucleus cross sections in and with KDAR neutrinos

    F Akbar🇮🇳 · M. Sajjad Athar🇮🇳 · S. K. Singh🇮🇳

    High intensity monoenergetic muon neutrinos of energy 236 MeV from kaon decay at rest (KDAR) at the medium energy proton accelerator facilities like J-PARC and Fermilab are proposed to be used for making precision measurements of neutrino-nucleus cross sections in and and perform neutrino oscillation experiments in and modes. In view of these developments, we study the theoretical uncertainties arising due to the nuclear medium effects in the neutrino-nucleus cross sections as well as in the angular and energy distributions of the charged leptons produced in the charged current (CC) induced reactions by and in and in the energy region of 300 MeV. The calculations have been done in a microscopic model using the local density approximation which takes into account the nuclear effects due to the Fermi motion, binding energy and long range correlations. The results are compared with the other calculations available in the literature.

    Comments:
    14 Pages, 12 Figures. arXiv admin note: text overlap with arXiv:1704.04582
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1708.00321 [pdf]
    J.Phys.G(2017)·12 citations
  4. 04

    [Submitted on 1 Aug 2017]

    Hollowness in pp scattering at the LHC

    Wojciech Broniowski🇵🇱 · Enrique Ruiz Arriola🇪🇸

    We examine how the effect of hollowness in pp scattering at the LHC (minimum of the inelasticity profile at zero impact parameter) depends on modeling of the phase of the elastic scattering amplitude as a function of the momentum transfer. We study the cases of the constant phase, the Bailly, and the so called standard parameterizations. It is found that the 2D hollowness holds in the first two cases, whereas the 3D hollowness is a robust effect, holding for all explored cases.

    Comments:
    Talk presented by WB at Excited QCD 2017, 7-13 May 2017, Sintra, Portugal, 6 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1708.00402 [pdf]
    Acta Phys.Polon.Supp.(2017)·14 citations
  5. 05

    [Submitted on 31 Jul 2017]

    A Study of Multi hypernuclei within Spherical Relativistic Mean-field Approach

    Asloob A. Rather · M. Ikram · A. A. Usmani · Bharat Kumar · S. K. Patra

    This research article is a follow up of earlier work by M. Ikram et al., reported in International Journal of Modern Physics E {\bf{25}}, 1650103 (2016) wherein we searched for magic numbers in experimentally confirmed doubly magic nucleonic cores in light to heavy mass region (ie.) by injecting 's into them. In present manuscript, working within the state-of-art relativistic mean field theory with inclusion of and interaction in hypernuclei using the predicted doubly magic nucleonic cores ie. 120, 120, 132, 132, 138, 138 of elusive superheavy mass regime. In analogy to well established signatures of magicity in conventional nuclear theory, the prediction of hypernuclear magicity are made on the basis of one-, two- separation energy () and two lambda shell gaps () in multi- hypernuclei. The calculations suggest that the numbers 92, 106, 126, 138, 184, 198, 240, and 258 might be the shell closures after introducing the 's in elusive superheavy nucleonic cores. Moreover, in support of shell closure the investigation of pairing energy and effective pairing gap has also been made. The appearance of new lambda shell closures other than the nucleonic ones predicted by various relativistic and non-relativistic theoretical investigations can be attributed to the relatively weak strength of spin-orbit coupling in hypernuclei compared to normal nuclei.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1708.00409 [pdf]
    Braz.J.Phys.(2017)·0 citations
  6. 06

    [Submitted on 1 Aug 2017]

    "Luneburg-lens-like structural Pauli attractive core of the nuclear force at short distances" [arXiv:1703.09396]

    Gerald A. Miller

    A recent paper [S. Ohkubo, Phys. Rev. C 95, 044002 (2017)] found that the measured 1S0 phase shifts can be reproduced using a deeply attractive nucleon-nucleon potential. We find that the deuteron would decay strongly via pion emission to the deeply bound state arising in this potential. There- fore the success of a deeply attractive potential in describing phase shifts must be regarded only as an interesting curiosity.

    Comments:
    2 pages 1 figure. This version includes the calculation of the model's predicted rate for pion-emission decay of the deuteron. This work is in press for Nucl. Phys. A. (2018)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1708.00412 [pdf]
    NPA(2018)·0 citations

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