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Nuclear Theory·nucl-th

Friday·October 27, 2017

11 papers—7 primary·4 cross-listed

All11Primary7Cross-lists4
  1. 01

    [Submitted on 25 Oct 2017]

    Decoding the phase structure of QCD via particle production at high energy

    A. Andronic🇩🇪 · P. Braun-Munzinger🇨🇳 · K. Redlich🇩🇪 · J. Stachel🇩🇪

    Recent studies based on non-perturbative lattice Monte-Carlo solutions of Quantum Chromodynamics, the theory of strong interactions, demonstrated that at high temperature there is a phase change from confined hadronic matter to a deconfined quark-gluon plasma where quarks and gluons can travel distances largely exceeding the size of hadrons. The phase structure of such strongly interacting matter can be decoded via analysis of particle abundances in high energy nuclear collisions within the framework of the statistical hadronization approach. The results imply quark-hadron duality at and experimental delineation of the location of the phase boundary of strongly interacting matter.

    Comments:
    15 pages, 8 figures; v2: final version accepted for publication in Nature
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1710.09425 [pdf]
    Nature(2018)·1002 citations
  2. 02

    [Submitted on 25 Oct 2017]

    12C within the Semimicroscopic Algebraic Cluster Model

    P. O. Hess

    The Semimicroscopic Algebraic Cluster Model (SACM) is applied to 12C as a system of three alpha- clusters. The microscopic model space, which observes the Pauli-Exclusion-Principle (PEP), is constructed. It is shown that the 12C nucleus can effectively be treated as a two-cluster system 8Be+alpha. The experimental spectrum is well reproduced. The geometrical mapping is discussed and it is shown that the ground state must correspond to a triangular structure, which is in agreement with other microscopic calculations. The non-zero B(E2; 0_2+ --> 2_1+) transition requires a mixing of SU(3) irreducible representations (irreps) whose consequences are discussed. The Hoyle state turns out to contain large shell excitations. The results are compared to another phenomenological model, which assumes a triangular structure and, using simple symmetry arguments, can reproduce the states observed at low energy. This model does not observe the PEP and one objective of our contribution is to verify the extend of importance of the PEP.

    Comments:
    8 pages, 3 figures, 8 tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1710.09428 [pdf]
    EPJA(2018)·14 citations
  3. 03

    [Submitted on 26 Oct 2017]

    Influence of final-state radiation on heavy-flavour observables in pp collisions

    L. Vermunt🇳🇱 · J. Aichelin🇫🇷 · P.B. Gossiaux🇫🇷 · K. Werner🇫🇷 · A. Mischke🇳🇱 · B. Guiot🇨🇱 · M. Nahrgang🇫🇷 · T. Pierog🇩🇪

    The influence of final-state radiation (FSR) of heavy quarks on observables in high-energy proton-proton collisions is studied. The transverse momentum correlation of D and Dbar mesons, which have been emitted with an azimuthal difference angle close to 180 degrees, is identified as an observable which is sensitive to the FSR process. We demonstrate this by performing calculations with the EPOS3+HQ model and with the event generator Pythia 6. The initial symmetric pT = pT' correlation for back-to-back pairs does not completely vanish in EPOS3+HQ, neither for the final DDbar pairs nor for the ccbar pairs before hadronisation. Also a significant difference in the shape of the correlation distribution for EPOS3+HQ and Pythia 6 is observed. Therefore, particle correlations in pp data offer the possibility to study several aspects of energy loss in heavy-ion collisions.

    Comments:
    8 pages, 6 figures, submitted to Eur. Phys. J. C, references added
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1710.09639 [pdf]
    3 citations
  4. 04

    [Submitted on 26 Oct 2017]

    Comparing standard distribution and its Tsallis form of transverse momenta in high energy collisions

    Rui-Fang Si🇨🇳 · Hui-Ling Li🇨🇳 · Fu-Hu Liu🇨🇳

    In this paper, the experimental (simulated) transverse momentum spectra of negatively charged pions produced at mid-rapidity in central nucleus-nucleus collisions at the Heavy Ion Synchrotron (SIS), Relativistic Heavy Ion Collider (RHIC), and Large Hadron Collider (LHC) energies obtained by different collaborations are selected by us to investigate, where a few simulated data are taken from the results of FOPI Collaboration who uses the IQMD transport code based on Quantum Molecular Dynamics. A two-component standard distribution and the Tsallis form of standard distribution are used to fit these data in the framework of a multisource thermal model. The excitation functions of main parameters in the two distributions are analyzed. In particular, the effective temperatures extracted from the two-component standard distribution and the Tsallis form of standard distribution are obtained, and the relation between the two types of effective temperatures is studied.

    Comments:
    22 pages, 8 figures. Advances in High Energy Physics, accepted
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1710.09645 [pdf]
    Adv.High Energy Phys.(2018)·13 citations
  5. 05

    [Submitted on 26 Oct 2017]

    Inelastic shadowing of secondary pi+-, K+-, p, and bar(p) produced in p+Pb collisions at LHC energy

    G.H. Arakelyan🇦🇲 · C. Merino🇪🇸 · Yu.M. Shabelski🇷🇺 · A.G. Shuvaev🇷🇺

    The inclusive spectra of secondaries produced in soft (minimum-bias) p+Pb collisions at LHC energy are calculated in the frame of the Quark-Gluon String Model, by including the inelastic screening corrections (percolation effects). These effects are expected to be quite large at the very high energies, and they should drive down the spectra in the midrapidity region more than 2 times, at sqrt(sNN)=5 TeV.

    Comments:
    Contribution to the Proceedings of the Low-x Meeting 2017, ed by C. Royon et al., Bisceglie, near Bari (Italy), June 13th-18th, 2017 (6 pages and 1 table)
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1710.09661 [pdf]
    0 citations
  6. 06

    [Submitted on 26 Oct 2017]

    Study of Lambda polarization at RHIC BES and LHC energies

    Iurii Karpenko🇮🇹 · Francesco Becattini🇮🇹

    In hydrodynamic approach to relativistic heavy ion collisions, hadrons with nonzero spin, produced out of the hydrodynamic medium, can acquire polarization via spin-vorticity thermodynamic coupling mechanism. The hydrodynamical quantity steering the polarization is the thermal vorticity, that is minus the antisymmetric part of the gradient of four-temperature field. Based on this mechanism there have been several calculations in hydrodynamic and non-hydrodynamic models for non-central heavy ion collisions in the RHIC Beam Energy Scan energy range, showing that the amount of polarization of produced hyperons ranges from few percents to few permille, and decreases with collision energy. We report on an extension of our existing calculation of global polarization in UrQMD+vHLLE model to full RHIC and LHC energies, and discuss the component of polarization along the beam direction, which is the dominant one at high energies.

    Comments:
    proceedings of Strangeness in Quark Matter 2017 conference. 4 pages, 2 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1710.09726 [pdf]
    EPJ Web Conf.(2018)·5 citations
  7. 07

    [Submitted on 26 Oct 2017]

    Electromagnetic reactions from coupled-cluster theory

    Sonia Bacca · Mirko Miorelli · Gaute Hagen

    We review recent results for electromagnetic reactions and related sum rules in light and medium-mass nuclei obtained from coupled-cluster theory. In particular, we highlight our recent computations of the photodisintegration cross section of 40Ca and of the electric dipole polarizability for oxygen and calcium isotopes. We also provide new results for the Coulomb sum rule for 4He and 16O. For 4He we perform a thorough comparison of coupled-cluster theory with exact hyperspherical harmonics.

    Comments:
    6 pages, 4 figures, proceedings of the 12th International Spring Seminar on Nuclear Physics 'Current Problems and Prospects for Nuclear Structure', Sant'Angelo d'Ischia, May 15 to 19, 2017
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1710.09741 [pdf]
    J.Phys.Conf.Ser.(2018)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE