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Nuclear Theory·nucl-th

Wednesday·November 18, 2015

7 papers—2 primary·5 cross-listed

All7Primary2Cross-lists5
  1. 03

    [Submitted on 16 Nov 2015] (cross-list from hep-th)

    The Skyrme model in the BPS limit

    C. Adam🇪🇸 · C. Naya🇪🇸 · J. Sanchez-Guillen🇪🇸 · R. Vazquez🇪🇸 · A. Wereszczynski🇵🇱

    In this review, we summarise the main features of the BPS Skyrme model which provides a physically well-motivated idealisation of atomic nuclei and nuclear matter: 1) it leads to zero binding energies for classical solitons (while realistic binding energies emerge owing to the semiclassical corrections, the Coulomb interaction and isospin breaking); 2) it describes a perfect non-barotropic fluid already at the microscopic (field theoretical) level which allows to study thermodynamics beyond the mean-field limit. These properties allow for an approximate but analytical calculation of binding energies of the most abundant nuclei, for a determination of the equation of state of skyrmionic matter (both in the full field theory and in a mean-field approximation) as well as the description of neutron stars as Skyrme solitons with a very good agreement with available observational data. All these results suggest that the proper low energy effective model of QCD should be close to the BPS Skyrme model in a certain sense (a "near-BPS Skyrme model"), with a prominent role played by the BPS part.

    Comments:
    40 pages, Latex, 10 figures. Contribution to: M. Rho, I. Zahed, Eds., The Multifaceted Skyrmion, 2nd Edition, World Scientific, Singapore
    Subjects:
    High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1511.05160 [pdf]
    19 citations
  2. 04

    [Submitted on 17 Nov 2015] (cross-list from hep-ph)

    A Study of Quasi-parton Distribution Functions in the Diquark Spectator Model

    Leonard Gamberg🇺🇸 · Zhong-Bo Kang🇺🇸 · Ivan Vitev🇺🇸 · Hongxi Xing🇺🇸

    To facilitate lattice QCD calculations of nucleon structute, a set of quasi-parton distributions were recently introduced. These quasi-PDFs were shown to reduce to standard PDFs when the nucleon is boosted to high energies, . Since taking such limit is not feasible in lattice simulations, it is essential to provide guidance for what values of the quasi-PDFs are good approximations of standard PDFs. Within the framework of the spectator diquark model, we evaluate both the up and down quarks' quasi-PDFs and standard PDFs for all leading-twist distributions (unpolarized distribution , helicity distribution , and transversity distribution ). We find that, for intermediate parton momentum fractions , quasi-PDFs are good approximations to standard PDFs (within ) when GeV. On the other hand, for large much larger GeV is necessary to obtain a satisfactory agreement between the two sets. We further find that the Soffer positivity bound does not hold in general for quasi-PDFs.

    Comments:
    10 pages, 5 eps figures, presented at QCD Evolution 2015
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1511.05242 [pdf]
    PoS(2015)·10 citations
  3. 05

    [Submitted on 17 Nov 2015] (cross-list from hep-ph)

    Energy loss of and mesons in PbPb collisions at = 2.76 TeV

    Kapil Saraswat🇮🇳 · Prashant Shukla🇮🇳 · Venktesh Singh🇮🇳

    We present the calculations of collisional and radiative energy loss of and mesons in the medium produced in PbPb collisions at = 2.76 TeV. The nuclear modification factor of and mesons including shadowing and energy loss are calculated and compared with the measured data. While the meson can be described in terms of the radiative energy loss alone, both the collisional as well as radiative energy loss are required to explain the meson measurements.

    Comments:
    arXiv admin note: substantial text overlap with arXiv:1507.06742
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1511.05349 [pdf]
    PoS(2015)·1 citation
  4. 06

    [Submitted on 17 Nov 2015] (cross-list from hep-ph)

    Concurrent tests of Lorentz invariance in -decay experiments

    K.K. Vos🇳🇱 · H.W. Wilschut🇳🇱 · R.G.E. Timmermans🇳🇱

    Modern experiments on neutron and allowed nuclear decay search for new semileptonic interactions, beyond the ``left-handed'' electroweak force. We show that ongoing and planned -decay experiments, with isotopes at rest and in flight, can be exploited as sensitive tests of Lorentz invariance. The variety of correlations that involve the nuclear spin, the direction of the emitted particle, and the recoil direction of the daughter nucleus allow for relatively simple experiments that give direct bounds on Lorentz violation. The pertinent observables are decay-rate asymmetries and their dependence on sidereal time. We discuss the potential of several asymmetries that together cover a large part of the parameter space for Lorentz violation in the gauge sector. High counting statistics is required.

    Comments:
    Accepted for publication as a Rapid communication in Phys. Rev. C
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1511.05400 [pdf]
    PRC(2015)·15 citations
  5. 07

    [Submitted on 17 Nov 2015] (cross-list from gr-qc)

    Quantum relativistic fluid at global thermodynamic equilibrium in curved spacetime

    F. Becattini🇮🇹 · E. Grossi (University of Florence)🇮🇹

    We present a new approach to the problem of the thermodynamical equilibrium of a quantum relativistic fluid in a curved spacetime in the limit of small curvature. We calculate the mean value of local operators by expanding the four-temperature Killing vector field in Riemann normal coordinates about the same spacetime point and we derive corrections with respect to the flat spacetime expressions. Thereby, we clarify the origin of the terms proportional to Riemann and Ricci tensors introduced in general hydrodynamic expansion of the stress-energy tensor.

    Comments:
    5 pages
    Subjects:
    General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1511.05439 [pdf]
    2 citations

Affiliations

first authorsco-authorsvia INSPIRE