PaperPanorama
FAQ

Nuclear Theory·nucl-th

Thursday·April 20, 2017

14 papers—9 primary·5 cross-listed

All14Primary9Cross-lists5
  1. 10

    [Submitted on 5 Apr 2017] (cross-list from astro-ph.SR)

    Reducing Uncertainties in the Production of the Gamma Emitting Nuclei 26Al, 44Ti, and 60Fe in Core Collapse Supernovae by Using Effective Helium Burning Rates

    Sam Austin · Christopher West · Alexander Heger

    We have used effective reaction rates (ERR) for the helium burning reactions to predict the yield of the gamma-emitting nuclei 26Al, 44Ti, and 60Fe in core col- lapse supernovae. The variations in the predicted yields for values of the reaction rates allowed by the ERR are much smaller than obtained previously, and smaller than other uncertainties. A "filter" for supernova nucleosynthesis yields based on pre-supernova structure was used to estimate the effect of failed supernovae on the initial mass function-averaged yields; this substantially reduced the yields of all these isotopes, but the predicted yield ratio 60Fe/26Al was little affected. The robustness of this ratio is promising for comparison with data, but it is larger than observed in nature; possible causes for this discrepancy are discussed.

    Comments:
    16 pages, 3 figures
    Subjects:
    Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1704.01240 [pdf]
    ApJL(2017)·9 citations
  2. 11

    [Submitted on 18 Apr 2017] (cross-list from hep-ph)

    The spin-dependent quark beam function at NNLO

    Radja Boughezal🇺🇸 · Frank Petriello🇺🇸 · Ulrich Schubert🇺🇸 · Hongxi Xing🇺🇸

    We calculate the beam function for longitudinally-polarized quarks through next-to-next-to-leading order (NNLO) in QCD perturbation theory. This is the last missing ingredient needed to apply the factorization theorem for the -jettiness event-shape variable in polarized collisions through the NNLO level. We present all technical details of our derivation. As a by-product of our calculation we provide the first independent check of the previously-obtained unpolarized quark beam function. We anticipate that our result will have phenomenological applications in describing data from polarized collisions.

    Comments:
    18 pages, 3 figures, references added, corrections made in some equations
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1704.05457 [pdf]
    PRD(2017)·20 citations
  3. 12

    [Submitted on 18 Apr 2017] (cross-list from hep-ph)

    Dynamical vs. equilibrium properties of the QCD phase transition: a holographic perspective

    Romulo Rougemont (IIP, Brazil)🇧🇷 · Renato Critelli (Sao Paulo U.)🇧🇷 · Jacquelyn Noronha-Hostler (Houston U.)🇺🇸 · Jorge Noronha (Sao Paulo U.)🇧🇷 · Claudia Ratti (Houston U.)🇺🇸

    We employ an Einstein-Maxwell-Dilaton (EMD) holographic model, which is known to be in good agreement with lattice results for the QCD equation of state with flavors and physical quark masses, to investigate the temperature and baryon chemical potential dependence of the susceptibilities, conductivities, and diffusion coefficients associated with baryon, electric, and strangeness conserved charges. We also determine how the bulk and shear viscosities of the plasma vary in the plane of temperature and baryon chemical potential. The diffusion of conserved charges and the hydrodynamic viscosities in a baryon rich quark-gluon plasma are found to be suppressed with respect to the zero net baryon case. The transition temperatures associated with equilibrium and non-equilibrium quantities are determined as a function of the baryon chemical potential for the first time. Because of the crossover nature of the QCD phase transition even at moderately large values of the chemical potential, we find that the transition temperatures associated with different quantities are spread in the interval between MeV and they all decrease with increasing baryon chemical potential.

    Comments:
    20 pages, 19 figures, version accepted for publication in Physical Review D
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1704.05558 [pdf]
    PRD(2017)·118 citations
  4. 13

    [Submitted on 19 Apr 2017] (cross-list from hep-ph)

    Breit-Wigner distribution, quantum beats and GSI Anomaly

    M. S. Hosseini🇮🇷 · S. A. Alavi🇮🇷

    The relationship between Breit-Wigner distribution as an underlying basis for decaying unstable quantum systems and GSI experiment (anomaly) has not been addressed properly in the literatures. We show that quantum beats can be obtained using a superposition of two Breit-Wigner distributions. This modified distribution can explain the GSI time anomaly with quantum beats resulting from the existence of two energy levels of the decaying ion.

    Comments:
    7 pages, 2 Figure
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    1704.05762 [pdf]
    Annals Phys.(2019)·1 citation
  5. 14

    [Submitted on 19 Apr 2017] (cross-list from hep-ph)

    On the large-Q^2 behavior of the pion transition form factor

    Gernot Eichmann🇵🇹 · Christian S. Fischer🇩🇪 · Esther Weil🇩🇪 · Richard Williams🇩🇪

    We study the transition of non-perturbative to perturbative QCD in situations with possible violations of scaling limits. To this end we consider the singly- and doubly-virtual pion transition form factor at all momentum scales of symmetric and asymmetric photon momenta within the Dyson-Schwinger/Bethe-Salpeter approach. For the doubly virtual form factor we find good agreement with perturbative asymptotic scaling laws. For the singly-virtual form factor our results agree with the Belle data. At very large off-shell photon momenta we identify a mechanism that introduces quantitative modifications to Efremov-Radyushkin-Brodsky-Lepage scaling.

    Comments:
    5 pages, 7 figures, v3:contents revised, version published in PLB
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    1704.05774 [pdf]
    PLB(2017)·49 citations

Affiliations

first authorsco-authorsvia INSPIRE