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Nuclear Theory·nucl-th

Monday·September 11, 2017

6 papers—3 primary·3 cross-listed

All6Primary3Cross-lists3
  1. 01

    [Submitted on 8 Sept 2017]

    Role of net baryon density on rapidity width of identified particles from the lowest energies available at the CERN Super Proton Synchrotron to those at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider

    Nur Hussain🇮🇳 · Buddhadeb Bhattacharjee🇮🇳

    Widths of the rapidity distributions of various identified hadrons generated with the UrQMD-3.4 event generator at all the Super Proton Synchrotron (SPS) energies have been presented and compared with the existing experimental results. An increase in the width of the rapidity distribution of could be seen with both Monte Carlo (MC) and experimental data for the studied energies. Using MC data, the study has been extended to Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies. A similar jump, as observed in the plot of rapidity width versus rest mass at Alternating Gradient Synchrotron (AGS) and all SPS energies, persists even at RHIC and LHC energies, confirming its universal nature from AGS to the highest LHC energies. Such observation indicates that pair production may not be the only mechanism of particle production at the highest LHC energies. However, with MC data, the separate mass scaling for mesons and baryons is found to exist even at the top LHC energy.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1709.02660 [pdf]
    PRC(2017)·6 citations
  2. 02

    [Submitted on 8 Sept 2017]

    Strangeness Production and Color Deconfinement

    Paolo Castorina · Salvatore Plumari · Helmut Satz

    The relative multiplicities for hadron production in different high energy collisions are in general well described by an ideal gas of all hadronic resonances, except that under certain conditions, strange particle rates are systematically reduced. We show that the suppression factor gamma_s, accounting for reduced strange particle rates in pp, pA and AA collisions at different collision energies, becomes a universal function when expressed in terms of the initial entropy density s_0 or the initial temperature T of the produced thermal medium. It is found that gamma_s increases from about 0.5 to 1.0 in a narrow temperature range around the quark-hadron transition temperature T_c = 160 MeV. Strangeness suppression thus disappears with the onset of color deconfinement; subsequently, full equilibrium resonance gas behavior is attained.

    Comments:
    7 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1709.02706 [pdf]
  3. 03

    [Submitted on 8 Sept 2017]

    Structure of the lightest tin isotopes

    T. D. Morris · J. Simonis · S. R. Stroberg · C. Stumpf · G. Hagen · J. D. Holt · G. R. Jansen · T. Papenbrock · R. Roth · A. Schwenk

    We link the structure of nuclei around Sn, the heaviest doubly magic nucleus with equal neutron and proton numbers (), to nucleon-nucleon () and three-nucleon () forces constrained by data of few-nucleon systems. Our results indicate that Sn is doubly magic, and we predict its quadrupole collectivity. We present precise computations of Sn based on three-particle--two-hole excitations of Sn, and reproduce the small splitting between the lowest and states. Our results are consistent with the sparse available data.

    Comments:
    8 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1709.02786 [pdf]
    PRL(2018)·248 citations
  4. 04

    [Submitted on 7 Sept 2017] (cross-list from astro-ph.HE)

    Two coexisting families of compact stars: observational implications for millisecond pulsars

    Sudip Bhattacharyya (1)🇮🇳 · Ignazio Bombaci (2, 3)🇮🇹 · Domenico Logoteta (3)🇮🇹 · Arun V. Thampan (4, 5) ((1) TIFR, India, (2) Universita di Pisa, (3) INFN, Italy, (4) St. Joseph's College, (5) IUCAA, India)🇮🇳

    It is usually thought that a single equation of state (EoS) model "correctly" represents cores of all compact stars. Here we emphasize that two families of compact stars, viz., neutron stars and strange stars, can coexist in nature, and that neutron stars can get converted to strange stars through the nucleation process of quark matter in the stellar center. From our fully general relativistic numerical computations of the structures of fast-spinning compact stars, known as millisecond pulsars, we find that such a stellar conversion causes a simultaneous spin-up and decrease in gravitational mass of these stars. This is a new type of millisecond pulsar evolution through a new mechanism, which gives rise to relatively lower mass compact stars with higher spin rates. This could have implication for the observed mass and spin distributions of millisecond pulsars. Such a stellar conversion can also rescue some massive, spin-supported millisecond pulsars from collapsing into black holes. Besides, we extend the concept of critical mass for the neutron star sequence (Berezhiani et al. 2003; Bombaci et al. 2004) to the case of fast-spinning neutron stars, and point out that neutron star EoS models cannot be ruled out by the stellar mass measurement alone. Finally, we emphasize the additional complexity for constraining EoS models, for example, by stellar radius measurements using X-ray observations, if two families of compact stars coexist.

    Comments:
    10 pages, 5 figures, accepted for publication in The Astrophysical Journal
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
    arXiv:
    1709.02415 [pdf]
    ApJ(2017)·18 citations
  5. 05

    [Submitted on 8 Sept 2017] (cross-list from nucl-ex)

    Observation of He+ cluster states in Li

    W. H. Ma · J. S. Wang · D. Patel · Y. Y. Yang · J. B. Ma · S. L. Jin · P. Ma · Q. Hu · Z. Bai · M. R. Huang · X. Q. Liu · Y. J. Zhou and 16 other authors

    He+ cluster states of exited Li have been measured by 32.7 MeV/nucleon Li beams bombarding on Pb target. Two resonant states are clearly observed with the excitation energies at 9.8 MeV and 12.6 MeV and spin-parity of 3/2 and 7/2 respectively. These two states are considered to be members of K=1/2 band. The spin-parity of them are identified by the method of angular correlation analysis and verified by the continuum discretized coupled channels (CDCC) calculation, which agrees with the prediction of the generator coordinate method (GCM). A monopole matrix element about 4 fm for the 3/2 state is extracted from the distorted wave Born approximation (DWBA) calculation. These results strongly support the feature of clustering structure of two neutron-rich clusters in the neutron-rich nucleus Li for the first time.

    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1709.02515 [pdf]
    PRC(2021)·14 citations
  6. 06

    [Submitted on 8 Sept 2017] (cross-list from hep-ph)

    Anisotropy in the equation of state of strongly magnetized quark matter within the Nambu--Jona-Lasinio Model

    Sidney S. Avancini🇧🇷 · Veronica Dexheimer🇺🇸 · Ricardo L. S. Farias🇧🇷 · Varese S. Timóteo🇧🇷

    In this article, we calculate the magnetization and other thermodynamical quantities for strongly magnetized quark matter within the Nambu-Jona-Lasinio model at zero temperature. We assume two scenarios, chemically equilibrated charge neutral matter present in the interior of compact stars and zero-strangeness isospin-symmetric matter created in nuclear experiments. We show that the magnetization oscillates with density but in a much more smooth form than what was previously shown in the literature. As a consequence, we do not see the unphysical behavior in the pressure in the direction perpendicular to the magnetic field that was previously found. Finally, we also analyze the effects of a vector interaction on our results.

    Comments:
    9 pages, 10 figures, replaced with version matching the one published in the Physical Review C
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1709.02774 [pdf]
    PRC(2018)·31 citations

Affiliations

first authorsco-authorsvia INSPIRE