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Nuclear Theory·nucl-th

Wednesday·April 22, 2015

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 01

    [Submitted on 20 Apr 2015]

    Ab Initio Approach to the Non-Perturbative Scalar Yukawa Model

    Yang Li🇺🇸 · V. A. Karmanov🇷🇺 · P. Maris🇺🇸 · J. P. Vary🇺🇸

    We report on the first non-perturbative calculation of the scalar Yukawa model in the single-nucleon sector up to four-body Fock sector truncation (one "scalar nucleon" and three "scalar pions"). The light-front Hamiltonian approach with a systematic non-perturbative renormalization is applied. We study the -body norms and the electromagnetic form factor. We find that the one- and two-body contributions dominate up to coupling . As we approach the coupling , we discover that the four-body contribution rises rapidly and overtakes the two- and three-body contributions. By comparing with lower sector truncations, we show that the form factor converges with respect to the Fock sector expansion.

    Comments:
    8 pages, 12 figures, to be published in Phys. Lett. B
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th)
    arXiv:
    1504.05233 [pdf]
    PLB(2015)·35 citations
  2. 02

    [Submitted on 21 Apr 2015]

    Well funneled nuclear structure landscape: renormalization

    A. Idini · G. Potel · F. Barranco · E. Vigezzi · R. A. Broglia

    A complete characterization of the structure of nuclei can be obtained by combining information arising from inelastic scattering, Coulomb excitation and decay, together with one- and two-particle transfer reactions. In this way it is possible to probe the single-particle and collective components of the nuclear many-body wavefunction resulting from their mutual coupling and diagonalising the low-energy Hamiltonian. We address the question of how accurately such a description can account for experimental observations. It is concluded that renormalizing empirically and on equal footing bare single-particle and collective motion in terms of self-energy (mass) and vertex corrections (screening), as well as particle-hole and pairing interactions through particle-vibration coupling allows theory to provide an overall, quantitative account of the data.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1504.05335 [pdf]
    PRC(2015)·29 citations
  3. 03

    [Submitted on 21 Apr 2015]

    Measured difference between 206Pb, 205Tl charge distributions and the proton 3s1/2 wave function

    M. R. Anders · S. Shlomo · I. Talmi

    Charge density difference between 206Pb and 205Tl, measured by elastic electron scattering, is very similar to the charge density due to a proton in a 3s1/2 orbit. We look for a potential well whose 3s1/2 wave function yields the measured data. We developed a novel method to obtain the potential directly from the density and its first and second derivatives. Fits to parametrized potentials were also carried out. The 3s1/2 wave functions of the potentials determined here, reproduce fairly well the experimental data within the quoted errors. To detect possible effects of short-range two-body correlations on the 3s1/2 shell model wave function, more accurate measurements are required.

    Comments:
    16 pages (double spaced), 4 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1504.05507 [pdf]
    3 citations
  4. 04

    [Submitted on 17 Apr 2015] (cross-list from hep-lat)

    Nucleon electromagnetic form factors in two-flavour QCD

    S. Capitani🇩🇪 · M. Della Morte🇩🇰 · D. Djukanovic🇩🇪 · G. von Hippel🇩🇪 · J. Hua🇩🇪 · B. Jäger🇬🇧 · B. Knippschild🇩🇪 · H.B. Meyer🇩🇪 · T.D. Rae🇩🇪 · H. Wittig🇩🇪

    We present results for the nucleon electromagnetic form factors, including the momentum transfer dependence and derived quantities (charge radii and magnetic moment). The analysis is performed using O(a) improved Wilson fermions in Nf=2 QCD measured on the CLS ensembles. Particular focus is placed on a systematic evaluation of the influence of excited states in three-point correlation functions, which lead to a biased evaluation, if not accounted for correctly. We argue that the use of summed operator insertions and fit ansätze including excited states allow us to suppress and control this effect. We employ a novel method to perform joint chiral and continuum extrapolations, by fitting the form factors directly to the expressions of covariant baryonic chiral effective field theory. The final results for the charge radii and magnetic moment from our lattice calculations include, for the first time, a full error budget. We find that our estimates are compatible with experimental results within their overall uncertainties.

    Comments:
    22 pages, 10 figures, citations modified
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1504.04628 [pdf]
    PRD(2015)·87 citations
  5. 05

    [Submitted on 20 Apr 2015] (cross-list from hep-th)

    Baryon chemical potential and in-medium properties of BPS skyrmions

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

    We continue the investigation of thermodynamical properties of the BPS Skyrme model. In particular, we analytically compute the baryon chemical potential both in the full field theory and in a mean-field approximation. In the full field theory case, we find that the baryon chemical potential is always exactly proportional to the baryon density, for arbitrary solutions. We further find that, in the mean-field approximation, the BPS Skyrme model approaches the Walecka model in the limit of high density - their thermodynamical functions as well as the equation of state agree in this limit. This fact allows to read off some properties of the -meson from the BPS Skyrme action, even though the latter model is entirely based on the (pionic) Skyrme field. On the other hand, at low densities, at the order of the usual nuclear matter density, the equations of state of the two models are no longer universal, such that a comparison depends on some model details. Still, also the BPS Skyrme model gives rise to nuclear saturation in this regime, leading, in fact, to an exact balance between repulsive and attractive forces. The perfect fluid aspects of the BPS Skyrme model, which, together with its BPS properties, form the base of our results, are shown to be in close formal analogy with the Eulerian formulation of relativistic fluid dynamics. Within this analogy, the BPS Skyrme model, in general, corresponds to a non-barotropic perfect fluid.

    Comments:
    Latex, 28 pages, 3 figures
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1504.05185 [pdf]
    PRD(2015)·27 citations
  6. 06

    [Submitted on 21 Apr 2015] (cross-list from hep-ph)

    Spin Physics at J-PARC

    S. Kumano🇯🇵

    Spin-physics projects at J-PARC are explained by including future possibilities. J-PARC is the most-intense hadron-beam facility in the high-energy region above multi-GeV, and spin physics will be investigated by using secondary beams of kaons, pions, neutrinos, muons, and antiproton as well as the primary-beam proton. In particle physics, spin topics are on muon , muon and neutron electric dipole moments, and time-reversal violation experiment in a kaon decay. Here, we focus more on hadron-spin physics as for future projects. For example, generalized parton distributions (GPDs) could be investigated by using pion and proton beams, whereas they are studied by the virtual Compton scattering at lepton facilities. The GPDs are key quantities for determining the three-dimensional picture of hadrons and for finding the origin of the nucleon spin including partonic orbital-angular-momentum contributions. In addition, polarized parton distributions and various hadron spin topics should be possible by using the high-momentum beamline. The strangeness contribution to the nucleon spin could be also investigated in principle with the neutrino beam with a near detector facility.

    Comments:
    10 pages, LaTeX, 12 eps files, Plenary talk, to be published in International Journal of Modern Physics: Conference Series, Proceedings of the 21st International Symposium on Spin Physics (Spin2014), Beijing, China, October 20-24, 2014
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1504.05264 [pdf]
    Int.J.Mod.Phys.Conf.Ser.(2016)·24 citations
  7. 07

    [Submitted on 21 Apr 2015] (cross-list from hep-lat)

    Thermodynamics of strong-interaction matter from Lattice QCD

    Heng-Tong Ding🇨🇳 · Frithjof Karsch🇩🇪 · Swagato Mukherjee🇺🇸

    We review results from lattice QCD calculations on the thermodynamics of strong-interaction matter with emphasis on input these calculations can provide to the exploration of the phase diagram and properties of hot and dense matter created in heavy ion experiments. This review is organized as follows: 1) Introduction, 2) QCD thermodynamics on the lattice, 3) QCD phase diagram at high temperature, 4) Bulk thermodynamics, 5) Fluctuations of conserved charges, 6) Transport properties, 7) Open heavy flavors and heavy quarkonia, 8) QCD in external magnetic fields, 9) Summary.

    Comments:
    Review to appear in QGP 5, 72 pages, 30 figures
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1504.05274 [pdf]
    IJMPE(2015)·459 citations

Affiliations

first authorsco-authorsvia INSPIRE