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Nuclear Theory·nucl-th

Tuesday·August 23, 2016

8 papers—4 primary·4 cross-listed

All8Primary4Cross-lists4
  1. 05

    [Submitted on 16 Aug 2016] (cross-list from hep-ph)

    The magnetic moments and electromagnetic form factors of the decuplet baryons in chiral perturbation theory

    Hao-Song Li🇨🇳 · Zhan-Wei Liu🇦🇺 · Xiao-Lin Chen🇨🇳 · Wei-Zhen Deng🇨🇳 · Shi-Lin Zhu🇨🇳

    We have systematically investigated the magnetic moments and magnetic form factors of the decuplet baryons to the next-to-next-leading order in the framework of the heavy baryon chiral perturbation theory. Our calculation includes the contributions from both the intermediate decuplet and octet baryon states in the loops. We also calculate the charge and magnetic dipole form factors of the decuplet baryons. Our results may be useful to the chiral extrapolation of the lattice simulations of the decuplet electromagnetic properties.

    Comments:
    23 pages, 6 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1608.04617 [pdf]
    PRD(2017)·22 citations
  2. 06

    [Submitted on 19 Aug 2016] (cross-list from hep-ph)

    The LPM effect in sequential bremsstrahlung: 4-gluon vertices

    Peter Arnold🇺🇸 · Han-Chih Chang🇺🇸 · Shahin Iqbal🇵🇰

    The splitting processes of bremsstrahlung and pair production in a medium are coherent over large distances in the very high energy limit, which leads to a suppression known as the Landau-Pomeranchuk-Migdal (LPM) effect. In this paper, we continue study of the case when the coherence lengths of two consecutive splitting processes overlap (which is important for understanding corrections to standard treatments of the LPM effect in QCD), avoiding soft-gluon approximations. In particular, this paper completes the calculation of the rate for real double gluon bremsstrahlung from an initial gluon with various simplifying assumptions (thick media; approximation; and large ) by now including processes involving 4-gluon vertices.

    Comments:
    35 pages, 17 figures [changes from v1: minor typo fixes and minor referencing updates]
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1608.05718 [pdf]
    JHEP(2016)·29 citations
  3. 07

    [Submitted on 20 Aug 2016] (cross-list from astro-ph.SR)

    Bayesian Estimation of Thermonuclear Reaction Rates

    Christian Iliadis🇺🇸 · Kevin Anderson🇺🇸 · Alain Coc🇫🇷 · Frank Timmes🇺🇸 · Sumner Starrfield🇺🇸

    The problem of estimating non-resonant astrophysical S-factors and thermonuclear reaction rates, based on measured nuclear cross sections, is of major interest for nuclear energy generation, neutrino physics, and element synthesis. Many different methods have been applied in the past to this problem, almost all of them based on traditional statistics. Bayesian methods, on the other hand, are now in widespread use in the physical sciences. In astronomy, for example, Bayesian statistics is applied to the observation of extra-solar planets, gravitational waves, and type Ia supernovae. However, nuclear physics, in particular, has been slow to adopt Bayesian methods. We present astrophysical S-factors and reaction rates based on Bayesian statistics. We develop a framework that incorporates robust parameter estimation, systematic effects, and non-Gaussian uncertainties in a consistent manner. The method is applied to the d(p,)He, He(He,2p)He, and He(,)Be reactions, important for deuterium burning, solar neutrinos, and big bang nucleosynthesis.

    Comments:
    8 Figures
    Subjects:
    Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
    arXiv:
    1608.05853 [pdf]
    ApJ(2016)·64 citations
  4. 08

    [Submitted on 22 Aug 2016] (cross-list from hep-ph)

    Quark self-energy in an ellipsoidally anisotropic quark-gluon plasma

    Babak S. Kasmaei🇺🇸 · Mohammad Nopoush🇺🇸 · Michael Strickland🇺🇸

    We calculate the quark self-energy in a quark-gluon plasma that possesses an ellipsoidal momentum-space anisotropy in the local rest frame. By introducing additional transverse momentum anisotropy parameters into the parton distribution functions, we generalize previous results which were obtained for the case of a spheroidal anisotropy. Our results demonstrate that the presence of anisotropies in the transverse directions affects the real and imaginary parts of quark self-energy and, consequently, the self-energy depends on both the polar and azimuthal angles in the local rest frame of the matter. Our results for the quark self-energy set the stage for the calculation of the effects of ellipsoidal momentum-space anisotropy on quark-gluon plasma photon spectra and collective flow.

    Comments:
    22 pages, 2 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1608.06018 [pdf]
    PRD(2016)·15 citations

Affiliations

first authorsco-authorsvia INSPIRE