PaperPanorama
FAQ

Nuclear Theory·nucl-th

Tuesday·July 28, 2015

10 papers—4 primary·6 cross-listed

All10Primary4Cross-lists6
  1. 05

    [Submitted on 25 Jul 2015] (cross-list from hep-ph)

    Stellar matter with pseudoscalar condensates

    A. A. Andrianov🇷🇺 · V. A. Andrianov🇷🇺 · D. Espriu🇪🇸 · S. S. Kolevatov🇷🇺

    In this work we consider how the appearance of gradients of pseudoscalar condensates in dense systems may possibly influence the transport properties of photons in such a medium as well as other thermodynamic characteristics. We adopt the hypothesis that in regions where the pseudoscalar density gradient is large the properties of photons and fermions are governed by the usual lagrangian extended with a Chern-Simons interaction for photons and a constant axial field for fermions. We find that these new pieces in the lagrangian produce non-trivial reflection coefficients both for photons and fermions when entering or leaving a region where the pseudoscalar has a non-zero gradient. A varying pseudoscalar density may also lead to instability of some fermion and boson modes and modify some properties of the Fermi sea. We speculate that some of these modifications could influence the cooling rate of stellar matter (for instance in compact stars) and have other observable consequences. While quantitative results may depend on precise astrophysical details most of the consequences are quite universal and consideration should be given to this possibility.

    Comments:
    14 pages,6 figures, the version to be published
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
    arXiv:
    1507.07087 [pdf]
    EPJC(2016)·4 citations
  2. 06

    [Submitted on 25 Jul 2015] (cross-list from hep-ph)

    Further study of the dibaryon within constituent quark models

    Hongxia Huang🇨🇳 · Jialun Ping🇨🇳 · Fan Wang🇨🇳

    Inspired by the discovery of the dibaryon and the experimental search of dibaryon with the STAR data, we study the strange dibaryon further in the framework of quark delocalization color screening model and chiral quark model. We have shown is a narrow resonance in D-wave scattering before. However, the - scattering data analysis is quite complicated. Here we calculate the low-energy scattering phase shifts, scattering length, effective range and binding energy to provide another approach of STAR data analysis. Our results show there exists an "bound" state, which can be observed by the - correlation analysis with RHIC and LHC data, or by the new developed automatic scanning system at J-PARC. Besides, we also find that the hidden color channel-coupling is important for the system to develop intermediate-range attraction.

    Comments:
    7 pages, 2 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1507.07124 [pdf]
    PRC(2015)·41 citations
  3. 07

    [Submitted on 26 Jul 2015] (cross-list from nucl-ex)

    Measurement of interaction between antiprotons

    STAR Collaboration

    One of the primary goals of nuclear physics is to understand the force between nucleons, which is a necessary step for understanding the structure of nuclei and how nuclei interact with each other. Rutherford discovered the atomic nucleus in 1911, and the large body of knowledge about the nuclear force since acquired was derived from studies made on nucleons or nuclei. Although antinuclei up to antihelium-4 have been discovered and their masses measured, we have no direct knowledge of the nuclear force between antinucleons. Here, we study antiproton pair correlations among data taken by the STAR experiment at the Relativistic Heavy Ion Collider and show that the force between two antiprotons is attractive. In addition, we report two key parameters that characterize the corresponding strong interaction: namely, the scattering length (f0) and effective range (d0). As direct information on the interaction between two antiprotons, one of the simplest systems of antinucleons, our result provides a fundamental ingredient for understanding the structure of more complex antinuclei and their properties.

    Comments:
    25 pages, 4 figures. Submitted to Nature. Under media embargo
    Subjects:
    Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    1507.07158 [pdf]
    Nature(2015)·130 citations
  4. 08

    [Submitted on 26 Jul 2015] (cross-list from astro-ph.HE)

    The many faces of strange matter: compact stars, cosmic rays, and dark matter

    Renxin Xu (PKU)

    The state of cold bulk matter at around nuclear density depends on the fundamental strong interaction between quarks at low-energy scale, so-called non-perturbative quantum chromo-dynamics. Such kind of matter is conjectured to be condensed matter of 3-flavour (u, d and s) quark clusters in this note, being manifested in the form of compact stars, cosmic rays, and even dark matter.

    Comments:
    3 pages, 1 figure. Proceeding of "Quarks and Compact Stars 2014 at KIAA (Beijing)"
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1507.07172 [pdf]
    Acta Astron.Sin.Suppl.(2015)·1 citation
  5. 09

    [Submitted on 27 Jul 2015] (cross-list from hep-ph)

    Testing the composite nature of the

    Ulf-G. Meißner🇩🇪 · José A. Oller🇪🇸

    Making use of a recently proposed formalism, we analyze the composite nature of the resonance observed by LHCb. We show that the present data suggest that this state is almost entirely made of a and a proton, due to the close proximity to this threshold. This also suppresses the decay modes into other, lighter channels, in our study represented by . We further argue that this is very similar to the case of the scalar meson which is located closely to the threshold and has a suppressed decay into the lighter channel.

    Comments:
    6 pages, 2 tables. One more grant is acknowledged
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    1507.07478 [pdf]
    PLB(2015)·202 citations
  6. 10

    [Submitted on 27 Jul 2015] (cross-list from hep-lat)

    The QCD phase diagram from analytic continuation

    R. Bellwied🇺🇸 · S. Borsanyi🇩🇪 · Z. Fodor🇩🇪 · J. Günther🇩🇪 · S. D. Katz🇭🇺 · C. Ratti🇺🇸 · K. K. Szabo🇩🇪

    We present the crossover line between the quark gluon plasma and the hadron gas phases for small real chemical potentials. First we determine the effect of imaginary values of the chemical potential on the transition temperature using lattice QCD simulations. Then we use various formulas to perform an analytic continuation to real values of the baryo-chemical potential. Our data set maintains strangeness neutrality to match the conditions of heavy ion physics. The systematic errors are under control up to MeV. For the curvature of the transition line we find that there is an approximate agreement between values from three different observables: the chiral susceptibility, chiral condensate and strange quark susceptibility. The continuum extrapolation is based on 10, 12 and 16 lattices. By combining the analysis for these three observables we find, for the curvature, the value .

    Comments:
    14 pages, 4 figures, revised version
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1507.07510 [pdf]
    PLB(2015)·292 citations

Affiliations

first authorsco-authorsvia INSPIRE