PaperPanorama
FAQ

Nuclear Theory·nucl-th

Friday·October 2, 2015

7 papers—5 primary·2 cross-listed

All7Primary5Cross-lists2
  1. 01

    [Submitted on 1 Oct 2015]

    The Coulomb interaction in Helium-3: Interplay of strong short-range and weak long-range potentials

    J. Kirscher · D. Gazit

    Quantum chromodynamics and the electroweak theory at low energies are prominent instances of the combination of a short-range and a long-range interaction. For the description of light nuclei, the large nucleon-nucleon scattering lengths produced by the strong interaction, and the reduction of the weak interaction to the Coulomb potential, play a crucial role. Helium-3 is the first bound nucleus comprised of more than one proton in which this combination of forces can be studied. We demonstrate a proper renormalization of Helium-3 using the pionless effective field theory as the formal representation of the nuclear regime as strongly interacting fermions. The theory is found consistent at leading and next-to-leading order without isospin-symmetry-breaking 3-nucleon interactions and a non-perturbative treatment of the Coulomb interaction. The conclusion highlights the significance of the regularization method since a comparison to previous work is contradictory if the difference in those methods is not considered. With a perturbative Coulomb interaction, as suggested by dimensional analysis, we find the Helium-3 system properly renormalized, too. For both treatments, renormalization-scheme independence of the effective field theory is demonstrated by regulating the potential and a variation of the associated cutoff.

    Comments:
    accepted version; additional figure; additional discussion of renorm. and limit cycle
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1510.00118 [pdf]
    PLB(2016)·18 citations
  2. 02

    [Submitted on 1 Oct 2015]

    Near-threshold photoproduction off nuclei

    E. Ya. Paryev🇷🇺 · Yu. T. Kiselev🇷🇺

    We study the photoproduction from nuclei near the kinematic threshold within the first collision model, based on the nuclear spectral function, for incoherent primary photon--nucleon charmonium creation processes. The model takes into account the final absorption, target nucleon binding and Fermi motion, the formation length of mesons as well as the effect of their nuclear mean-field potential on these processes. We calculate the A dependences of the absolute and relative (transparency ratio) charmonium yields as well as its absolute and relative excitation functions within the different scenarios for the absorption cross section, for the formation length and for in-medium modification. We demonstrate that the studied observables, on the one hand, are not practically affected by the charmonium formation length and mass shift effects and, on the other hand, they are appreciably sensitive to the genuine absorption cross section at above threshold beam energies, which means that these observables can be useful to help determine the absorption cross section from the comparison of the results of our calculations with the future data from the experiments in the Hall C at the upgraded up to 12 GeV CEBAF facility. We also show that the absolute and relative excitation functions for subthreshold production in reactions reveal some sensitivity to adopted in-medium modification scenarios for mesons. Therefore, such observables, measured in the subthreshold energy domain, may be an important tool to get valuable information on the charmonium in-medium properties in cold nuclear matter.

    Comments:
    16 pages. arXiv admin note: substantial text overlap with arXiv:1409.2428
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1510.00155 [pdf]
    4 citations
  3. 03

    [Submitted on 1 Oct 2015]

    A description of the pseudorapidity distributions in heavy ion collisions at RHIC and LHC energies

    Z. J. Jiang🇨🇳 · Y Zhang🇨🇳 · H. L. Zhang🇨🇳 · H. P. Deng🇨🇳

    The charged particles produced in nucleus-nucleus collisions are classified into two parts,One is from the hot and dense matter created in collisions. The other is from leading particles. The hot and dense matter is assumed to expand and generate particles according to BJP hydrodynamics, a theory put forward by A. Bialas, R. A. Janik and R. Peschanski. The leading particles are argued to possess a Gaussian rapidity distribution with the normalization constant equaling the number of participants. A comparison is made between the theoretical results and the experimental measurements performed by BRAHMS and PHOBOS Collaboration at BNL-RHIC in Au-Au and Cu-Cu collisions at sqrt(s_NN)=200 GeV and by ALICE Collaboration at CERN-LHC in Pb-Pb collisions at sqrt(s_NN) =2.76 TeV. The theoretical results are well consistent with experimental data.

    Comments:
    arXiv admin note: substantial text overlap with arXiv:1401.0768
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1510.00160 [pdf]
    NPA(2015)·20 citations
  4. 04

    [Submitted on 1 Oct 2015]

    Stable hybrid stars within a SU(3) Quark-Meson-Model

    Andreas Zacchi🇩🇪 · Matthias Hanauske🇩🇪 · Jürgen Schaffner-Bielich🇩🇪

    The inner regions of the most massive compact stellar objects might be occupied by a phase of quarks. Since the observations of the massive pulsars PSR J1614-2230 and of PSR J0348+0432 with about two solar masses, the equations of state constructing relativistic stellar models have to be constrained respecting these new limits. We discuss stable hybrid stars, i.e. compact objects with an outer layer composed of nuclear matter and with a core consisting of quark matter (QM). For the outer nuclear layer we utilize a density dependent nuclear equation of state and we use a chiral SU(3) Quark-Meson model with a vacuum energy pressure to describe the objects core. The appearance of a disconnected mass-radius branch emerging from the hybrid star branch implies the existence of a third family of compact stars, so called twin stars. Twin stars did not emerge as the transition pressure has to be relatively small with a large jump in energy density, which could not be satisfied within our approach. This is, among other reasons, due to the fact that the speed of sound in QM has to be relatively high, which can be accomplished by an increase of the repulsive coupling. This increase on the other hand yields too high transition pressures for twins stars to appear.

    Comments:
    13 pages, 20 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    1510.00180 [pdf]
    PRD(2016)·53 citations
  5. 05

    [Submitted on 1 Oct 2015]

    Electron Scattering Intensities and Patterson Functions of Skyrmions

    M. Karliner🇮🇱 · C. King🇬🇧 · N.S. Manton🇬🇧

    The scattering of electrons off nuclei is one of the best methods of probing nuclear structure. In this paper we focus on electron scattering off nuclei with spin and isospin zero within the Skyrme model. We consider two distinct methods and simplify our calculations by use of the Born approximation. The first method is to calculate the form factor of the spherically averaged Skyrmion charge density; the second uses the Patterson function to calculate the scattering intensity off randomly oriented Skyrmions, and spherically averages at the end. We compare our findings with experimental scattering data. We also find approximate analytical formulae for the first zero and first stationary point of a form factor.

    Comments:
    24 pages, 38 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th)
    arXiv:
    1510.00280 [pdf]
    J.Phys.G(2016)·8 citations
  6. 06

    [Submitted on 30 Sept 2015] (cross-list from nucl-ex)

    Longitudinal Spin Physics at RHIC and a Future eRHIC

    Brian Page🇺🇸

    Recent highlights from the spin program at the Relativistic Heavy Ion Collider (RHIC), focusing on the gluon contribution to the proton spin and the polarization of the light flavor sea, are presented. The impact of these data on recent global fits by the DSSV and NNPDF groups is also discussed. Finally, this note examines the constraints on the longitudinal spin structure of the proton which would be possible with a proposed eRHIC facility.

    Comments:
    Talk presented CIPANP2015. 10 pages, LaTeX, 5 figures
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1510.00076 [pdf]
    1 citation
  7. 07

    [Submitted on 1 Oct 2015] (cross-list from hep-ph)

    Nucleon structure functions at small via holographic Pomeron exchange

    Akira Watanabe🇹🇼 · Katsuhiko Suzuki🇯🇵

    The analysis on nucleon structure functions at small Bjorken in the framework of holographic QCD is presented. In the model setup, the complicated nonperturbative interaction between the virtual photon and the target nucleon is described via the Pomeron exchange, which corresponds to the reggeized graviton exchange in the AdS space. We show that our calculations for both and structure functions are in agreement with the experimental data measured at HERA.

    Comments:
    4 pages, 2 figures, contribution to the proceedings of the 10th International Workshop on the Physics of Excited Nucleons (NSTAR2015), 25-28 May 2015, Osaka, Japan
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1510.00153 [pdf]
    JPS Conf.Proc.(2016)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE