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Nuclear Theory·nucl-th

Tuesday·September 11, 2018

14 papers—9 primary·5 cross-listed

All14Primary9Cross-lists5
  1. 10

    [Submitted on 7 Sept 2018] (cross-list from hep-ph)

    Measuring the Weizsaecker-Williams distribution of linearly polarized gluons at an EIC through dijet azimuthal asymmetries

    Adrian Dumitru🇺🇸 · Vladimir Skokov🇺🇸 · Thomas Ullrich🇺🇸

    The production of a hard dijet with small transverse momentum imbalance in semi-inclusive DIS probes the conventional and linearly polarized Weizsaecker-Williams (WW) Transverse Momentum Dependent (TMD) gluon distributions. The latter, in particular, gives rise to an azimuthal dependence of the dijet cross-section. In this paper we analyze the feasibility of a measurement of these TMDs through dijet production in DIS on a nucleus at an Electron-Ion Collider. We introduce the MCDijet Monte-Carlo generator to sample quark-antiquark dijet configurations based on leading order parton level cross-sections with WW gluon distributions that solve the non-linear small-x QCD evolution equations. These configurations are fragmented to hadrons using PYTHIA, and final state jets are reconstructed. We report on background studies and on the effect of kinematic cuts introduced to remove beam jet remnants. We estimate that with an integrated luminosity of 20 fb^{-1}/A one can determine the distribution of linearly polarized gluons with a statistical accuracy of approximately 5%.

    Comments:
    28 pages, 14 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1809.02615 [pdf]
    PRC(2019)·79 citations
  2. 11

    [Submitted on 7 Sept 2018] (cross-list from nucl-ex)

    Consistent account of deuteron-induced reactions on Cr up to 60 MeV

    E. Simeckova · M. Avrigeanu · U. Fischer · J. Mrazek · J. Novak · M. Stefanik · C. Costache · V. Avrigeanu

    Purpose: Accurate new measurements of low-energy deuteron-induced reaction cross sections for natural Cr target can enhance the related database and the opportunity for an unitary and consistent account of the involved reaction mechanisms. Methods: The activation cross sections of Mn, Cr, and V nuclei for deuterons incident on natural Cr at energies up to 20 MeV, were measured by the stacked-foil technique and high resolution gamma spectrometry using U-120M cyclotron of the Center of Accelerators and Nuclear Analytical Methods (CANAM) of the Nuclear Physics Institute of the Czech Academy of Sciences (NPI CAS). They as well as formerly available data for deuteron interactions with Cr isotopes up to 60 MeV are the object of an extended analysis of all processes from elastic scattering until the evaporation from fully equilibrated compound system, but with a particular attention given to the BU and DR mechanisms. Results: The new measured activation excitation functions proved essential for the enrichment of the deuteron database, while the theoretical analysis of all available data strengthens for the first time their consistent account provided that (i) a suitable BU and DR assessment is completed by (ii) the assumption of PE and CN contributions corrected for decrease of the total-reaction cross section due to the leakage of the initial deuteron flux towards BU and DR processes. Conclusions: The suitable description of nuclear mechanisms involved within deuteron-induced reactions on chromium, taking into account especially the BU and DR direct processes, is validated by an overall agreement of the calculated and measured cross sections including particularly the new experimental data at low energies.

    Comments:
    15 pages, 14 figures, accepted for publication in Phys. Rev. C
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1809.02706 [pdf]
    PRC(2018)·11 citations
  3. 12

    [Submitted on 8 Sept 2018] (cross-list from hep-ph)

    Augmenting the Gauge-Gravity Correspondence to include Hadron Polarizabilities

    Pervez Hoodbhoy🇵🇰

    ADS/CFT models have achieved considerable success in describing hadronic properties such as masses and Regge trajectories. Even if the minimal vertex that couples photons to structureless spin-zero fields is used, one still ends up with electromagnetic form factors of hadrons that are in fair to good agreement with experiment. However, contradicting both experiment and intuition, this minimal model gives zero for hadronic electric and magnetic polarizabilities. We show here that if effective vertices are used, and axial and vector mesons are allowed to propagate as intermediate states, then the static polarizabilities can in principle be computed from ADS/CFT.

    Comments:
    11 pages, explanations added, results unchanged
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1809.02788 [pdf]
    PRD(2018)·0 citations
  4. 13

    [Submitted on 8 Sept 2018] (cross-list from hep-ph)

    Fractal structure of hadrons and non-extensive statistics

    Eugenio Megias🇪🇸 · Airton Deppman🇧🇷 · Tobias Frederico🇧🇷 · Debora P. Menezes🇧🇷

    The role played by non-extensive thermodynamics in physical systems has been under intense debate for the last decades. Some possible mechanisms that could give rise to non-extensive statistics have been formulated along the last few years, in particular the existence of a fractal structure in thermodynamic functions for hadronic systems. We investigate the properties of such fractal thermodynamical systems, in particular the fractal scale invariance is discussed in terms of the Callan-Symanzik~equation. Finally, we propose a diagrammatic method for calculations of relevant quantities.

    Comments:
    5 pages, 2 figures. Presented by E.Megias at the QCD@Work: International Workshop on QCD, 25-28 June 2018, Matera, Italy
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Statistical Mechanics (cond-mat.stat-mech); Nuclear Theory (nucl-th)
    arXiv:
    1809.02830 [pdf]
    EPJ Web Conf.(2018)·0 citations
  5. 14

    [Submitted on 10 Sept 2018] (cross-list from hep-ph)

    Chiral phase transition within the linear sigma model in the Tsallis nonextensive statistics based on density operator

    Masamichi Ishihara🇯🇵

    We studied the chiral phase transition for small within the Tsallis nonextensive statistics of the entropic parameter , where the quantity is the measure of the deviation from the Boltzmann-Gibbs statistics. We adopted the normalized -expectation value in this study. We applied the free particle approximation and the massless approximation in the calculations of the expectation values. We estimated the critical physical temperature, and obtained the chiral condensate, the sigma mass, and the pion mass, as functions of the physical temperature for various . We found the following facts. The -dependence of the critical physical temperature is . The chiral condensate at is smaller than that at for . The -dependence of the pion mass and that of the sigma mass reflect the -dependence of the condensate. The pion mass at is heavier than that at for . The sigma mass at is heavier than that at for at high physical temperature, while the sigma mass at is lighter than that at for at low physical temperature. The quantities which are functions of the physical temperature and the entropic parameter are described by only the effective physical temperature defined as under the approximations.

    Comments:
    12 pages, 3 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1809.03128 [pdf]
    IJMPE(2019)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE