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Nuclear Theory·nucl-th

Friday·February 6, 2015

11 papers—5 primary·6 cross-listed

All11Primary5Cross-lists6
  1. 06

    [Submitted on 4 Feb 2015] (cross-list from hep-th)

    Center symmetry and Hagedorn spectrum

    Adi Armoni🇬🇧 · Thomas D. Cohen🇺🇸 · Srimoyee Sen🇺🇸

    This paper explores the conjecture that large Nc gauge theories have a Hagedorn spectrum, if, and only if, they are confining and posses an explicit or emergent center symmetry. Evidence in support of this conjecture is presented. Many classes of large Nc gauge theories are considered. In all cases, we find that theories for which there exists a strong plausibility argument for a Hagedorn spectrum at large Nc are also believed to be confining and possess either an explicit center symmetric or have a strong plausibility argument for the existence of an emergent center symmetry at large Nc . Conversely, all theories we considered which are believed not to have a Hagedorn spectrum at large Nc, either were known not to be confining or else were believed to lack an emergent center symmetry. This is consistent with expectations based on the conjecture.

    Comments:
    expanded version. few references and one author added
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1502.01356 [pdf]
    PRD(2015)·4 citations
  2. 07

    [Submitted on 5 Feb 2015] (cross-list from astro-ph.HE)

    The effects of delta mesons on the baryonic direct Urca processes in neutron star matter

    Xiu-Lin Huang · Hai-Jun Wang · Guang-Zhou Liu · Yan Xu

    In the framework of relativistic mean field theory, the relativistic neutrino emissivity of the nucleonic and hyperonic direct Urca processes in the degenerate baryon matter of neutron stars are studied. We investigate particularly the influence of the isovector scalar interaction which is considered by exchanging meson on the nucleonic and hyperonic direct Urca processes. The results indicate that mesons lead to obvious enhancement of the total neutrino emissivity, which must result in more rapid cooling rate of neutron star matter.

    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1502.01460 [pdf]
    CPC(2015)·3 citations
  3. 08

    [Submitted on 5 Feb 2015] (cross-list from cond-mat.mes-hall)

    Generalized Bloch theorem and chiral transport phenomena

    Naoki Yamamoto🇯🇵

    Bloch theorem states the impossibility of persistent electric currents in the ground state of nonrelativistic fermion systems. We extend this theorem to generic systems based on the gauged particle number symmetry and study its consequences on the example of chiral transport phenomena. We show that the chiral magnetic effect can be understood as a generalization of the Bloch theorem to a nonequilibrium steady state, similarly to the integer quantum Hall effect. On the other hand, persistent axial currents are not prohibited by the Bloch theorem and they can be regarded as Pauli paramagnetism of relativistic matter. An application of the generalized Bloch theorem to quantum time crystals is also discussed.

    Comments:
    9 pages, 1 figure; v3: published version
    Subjects:
    Mesoscale and Nanoscale Physics (cond-mat.mes-hall); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    1502.01547 [pdf]
    PRD(2015)·116 citations
  4. 09

    [Submitted on 5 Feb 2015] (cross-list from hep-ph)

    Weak generalized form factors and transverse transition quark-spin density from the instanton vacuum

    Hyeon-Dong Son🇰🇷 · Seung-il Nam🇰🇷 · Hyun-Chul Kim🇰🇷

    We investigate the generalized transition vector and tensor form factors, from which we derive the transverse quark spin density in the course of the transition, based on the nonlocal chiral quark model from the instanton vacuum. The results of the transition tensor form factor are in good agreement with recent data of lattice QCD. The behavior of the transverse quark spin density of the transition turn out to be very similar to those of the pion and the kaon.

    Comments:
    11 pages, 5 figures. A few more sentences were added
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    1502.01558 [pdf]
    PLB(2015)·7 citations
  5. 10

    [Submitted on 5 Feb 2015] (cross-list from hep-ph)

    Non-extensive statistics effects in transverse momentum spectra of hadrons

    A.S. Parvan🇷🇺

    The Bose-Einstein and Fermi-Dirac statistics of the identified hadrons were verified on the basis of the transverse momentum distributions of bosons and fermions created in the collisions at high energies using the Tsallis-factorized statistics and the two-component distributions of the Boltzmann-Gibbs statistics. The main differences between the parameters of the Tsallis-factorized statistics and the Boltzmann-Gibbs statistics were identified. The results of the Boltzmann-Gibbs statistics are reasonable and suggest that the soft and hard hadrons may be produced from the two different macroscopic states of the dynamical system. It was revealed that the volume of the system obtained in the Tsallis-factorized statistics is unusually large in comparison with the geometrical volume of two protons. The main formulas for the Tsallis statistics in the grand canonical ensemble were formulated.

    Comments:
    2 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1502.01581 [pdf]
    PoS(2015)·5 citations
  6. 11

    [Submitted on 5 Feb 2015] (cross-list from hep-ph)

    Heavy quark scattering and quenching in a QCD medium at finite temperature and chemical potential

    H. Berrehrah🇩🇪 · E. Bratkovskaya🇩🇪 · W. Cassing🇩🇪 · P.B. Gossiaux🇫🇷 · J. Aichelin🇫🇷

    The heavy quark collisional scattering on partons of the quark gluon plasma (QGP) is studied in a QCD medium at finite temperature and chemical potential. We evaluate the effects of finite parton masses and widths, finite temperature and quark chemical potential on the different elastic cross sections for dynamical quasi-particles (on- and off-shell particles in the QGP medium as described by the dynamical quasi-particles model "DQPM") using the leading order Born diagrams. Our results show clearly the decrease of the and total elastic cross sections when the temperature and the quark chemical potential increase. These effects are amplified for finite at temperatures lower than the corresponding critical temperature . Using these cross sections we, furthermore, estimate the energy loss and longitudinal and transverse momentum transfers of a heavy quark propagating in a finite temperature and chemical potential medium. Accordingly, we have shown that the transport properties of heavy quarks are sensitive to the temperature and chemical potential variations. Our results provide some basic ingredients for the study of charm physics in heavy-ion collisions at Beam Energy Scan (BES) at RHIC and CBM experiment at FAIR.

    Comments:
    19 pages, 28 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1502.01700 [pdf]
    PRC(2015)·20 citations

Affiliations

first authorsco-authorsvia INSPIRE