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Nuclear Theory·nucl-th

Wednesday·March 9, 2016

11 papers—7 primary·4 cross-listed

All11Primary7Cross-lists4
  1. 08

    [Submitted on 8 Mar 2016] (cross-list from hep-ph)

    Coupled channel analysis of molecule picture of

    Yuki Shimizu🇯🇵 · Daiki Suenaga🇯🇵 · Masayasu Harada🇯🇵

    We construct a potential obtained by one-pion exchange for the coupled channel -, and solve the coupled Schrödinger equations to determine the binding energy. We find that there exists one or two bound states with the binding energy of several MeV below the threshold of and , dominantly made from a baryon and a meson, with the size of about fm for wide parameter region. We also study the pentaquark states including a quark and/or an anti- quark. We show that there exist pentaquarks including , and , all of which lie at about MeV below the corresponding threshold and have size of about fm.

    Comments:
    7 pages, 9 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1603.02376 [pdf]
    PRD(2016)·82 citations
  2. 09

    [Submitted on 8 Mar 2016] (cross-list from hep-ph)

    On the pole content of coupled channels chiral approaches used for the system

    A. Cieplý🇨🇿 · M. Mai🇩🇪 · Ulf-G. Meißner🇩🇪 · J. Smejkal🇨🇿

    Several theoretical groups describe the antikaon-nucleon interaction at low energies within approaches based on the chiral SU(3) dynamics and including next-to-leading order contributions. We present a comparative analysis of the pertinent models and discuss in detail their pole contents. It is demonstrated that the approaches lead to very different predictions for the amplitude extrapolated to subthreshold energies as well as for the amplitude. The origin of the poles generated by the models is traced to the so-called zero coupling limit, in which the inter-channel couplings are switched off. This provides new insights into the pole contents of the various approaches. In particular, different concepts of forming the resonance are revealed and constraints related to the appearance of such poles in a given approach are discussed.

    Comments:
    24 pages, 15 figures, to appear in Nuclear Physics A special issue on Strangeness and Charm Nuclear Physics; v2 - several paragraphs modified or extended, version accepted for publication
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1603.02531 [pdf]
    NPA(2016)·116 citations
  3. 10

    [Submitted on 8 Mar 2016] (cross-list from nucl-ex)

    From the stable to the exotic: clustering in light nuclei

    C. Beck🇫🇷

    A great deal of research work has been undertaken in alpha-clustering study since the pioneering discovery of 12C+12C molecular resonances half a century ago. Our knowledge on physics of nuclear molecules has increased considerably and nuclear clustering remains one of the most fruitful domains of nuclear physics, facing some of the greatest challenges and opportunities in the years ahead. The occurrence of "exotic" shapes in light N=Z alpha-like nuclei is investigated. Various approaches of the superdeformed and hyperdeformed bands associated with quasimolecular resonant structures are presented. Evolution of clustering from stability to the drip-lines is examined: clustering aspects are, in particular, discussed for light exotic nuclei with large neutron excess such as neutron-rich Oxygen isotopes with their complete spectroscopy.

    Comments:
    15 pages, 5 figures, Presented at the International Symposium on "New Horizons in Fundamental Physics - From Neutrons Nuclei via Superheavy Elements and Supercritical Fields to Neutron Stars and Cosmic Rays" held at Makutsi Safari Farm, South Africa, December 23-29, 2015. arXiv admin note: substantial text overlap with arXiv:1402.6590, arXiv:1303.0960, arXiv:1408.0684, arXiv:1011.3423
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1603.02574 [pdf]
    FIAS Interdisc.Sci.Ser.(2017)·4 citations
  4. 11

    [Submitted on 8 Mar 2016] (cross-list from astro-ph.HE)

    Influence of the stiffness of the equation of state and in-medium effects on the cooling of compact stars

    H. Grigorian🇷🇺 · D. N. Voskresensky🇷🇺 · D. Blaschke🇷🇺

    Measurements demonstrate the existence of compact stars with masses in a broad range from 1.2 to 2 . The most massive of these objects might be hybrid stars. To fulfill the constraint with a reserve we exploit the stiff DD2 hadronic equation of state (EoS) without and with excluded volume (DD2vex) correction, which produce maximum neutron star masses of and , respectively. We show that the stiffness of the EoS does not preclude an explanation of the whole set of cooling data within "nuclear medium cooling" scenario for compact stars by a variation of the star masses. We select appropriate proton gap profiles from those exploited in the literature and allow for a variation of the effective pion gap controlling the efficiency of the medium modified Urca process. However, we suppress the possibility of pion condensation. In general, the stiffer the EoS the steeper a decrease with density of the effective pion gap is required. Results are compared with previously obtained ones for the HDD EoS for which . The cooling of the compact star in the supernova remnant Cassiopeia A (Cas A) is explained mainly by an efficient medium modified Urca process. With the DD2vex EoS and using an effective pion gap steeper decreasing with the density and/or a proton gap shifted to smaller densities we are also able to reproduce both a strong decline compatible with ACIS-S data and HRC-S instrument data. The mass of Cas A is estimated as , above the value , which we have evaluated with the softer HDD equation of state. Different mass choices for the hottest object XMMU J173203.3-344518 are discussed. We make general remarks also on hybrid star cooling and on its dependence on the stiffness of the hadronic EoS.

    Comments:
    25 pages, 21 figures, to appear in the EPJA Topical Issue on "Exotic Matter in Neutron Stars"; a strongly abridged version of this work has been presented as eConf C140926 in the Proceedings of the Conference "Compact Stars in the QCD Phase Diagram IV", Prerow, September 26 - 30, 2014; arxiv:1507.04656
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1603.02634 [pdf]
    EPJA(2016)·40 citations

Affiliations

first authorsco-authorsvia INSPIRE