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Nuclear Theory·nucl-th

Wednesday·December 2, 2015

11 papers—4 primary·7 cross-listed

All11Primary4Cross-lists7
  1. 05

    [Submitted on 30 Nov 2015] (cross-list from hep-ph)

    Initial-state splitting kernels in cold nuclear matter

    Grigory Ovanesyan🇺🇸 · Felix Ringer🇺🇸 · Ivan Vitev🇺🇸

    We derive medium-induced splitting kernels for energetic partons that undergo interactions in dense QCD matter before a hard-scattering event at large momentum transfer . Working in the framework of the effective theory , we compute the splitting kernels beyond the soft gluon approximation. We present numerical studies that compare our new results with previous findings. We expect the full medium-induced splitting kernels to be most relevant for the extension of initial-state cold nuclear matter energy loss phenomenology in both p+A and A+A collisions.

    Comments:
    8 pages, 4 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1512.00006 [pdf]
    PLB(2016)·14 citations
  2. 06

    [Submitted on 30 Nov 2015] (cross-list from hep-ph)

    Aspects of QCD Current Algebra on a Null Plane

    Silas R. Beane🇺🇸 · Timothy J. Hobbs🇺🇸

    Consequences of QCD current algebra formulated on a light-like hyperplane are derived for the forward scattering of vector and axial-vector currents on an arbitrary hadronic target. It is shown that current algebra gives rise to a special class of sum rules that are direct consequences of the independent chiral symmetry that exists at every point on the two-dimensional transverse plane orthogonal to the lightlike direction. These sum rules are obtained by exploiting the closed, infinite-dimensional algebra satisfied by the transverse moments of null-plane axial-vector and vector charge distributions. In the special case of a nucleon target, this procedure leads to the Adler-Weisberger, Gerasimov-Drell-Hearn, Cabbibo-Radicatti and Fubini-Furlan-Rossetti sum rules. Matching to the dispersion-theoretic language which is usually invoked in deriving these sum rules, the moment sum rules are shown to be equivalent to algebraic constraints on forward S-matrix elements in the Regge limit.

    Comments:
    38 pages, 2 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1512.00098 [pdf]
    Annals Phys.(2016)·5 citations
  3. 07

    [Submitted on 1 Dec 2015] (cross-list from astro-ph.SR)

    Electron capture and beta-decay rates for sd-shell nuclei in stellar environments relevant to high density O-Ne-Mg cores

    Toshio Suzuki · Hiroshi Toki · Ken'ichi Nomoto

    Electron capture and beta-decay rates for nuclear pairs in sd-shell are evaluated at high densities and high temperatures relevant to the final evolution of electron-degenerate O-Ne-Mg cores of stars with the initial masses of 8-10 solar mass. Electron capture induces a rapid contraction of the electron-degenerate O-Ne-Mg core. The outcome of rapid contraction depends on the evolutionary changes in the central density and temperature, which are determined by the competing processes of contraction, cooling, and heating. The fate of the stars are determined by these competitions, whether they end up with electron-capture supernovae or Fe core-collapse supernovae. Since the competing processes are induced by electron capture and beta-decay, the accurate weak rates are crucially important. The rates are obtained for pairs with A=20, 23, 24, 25 and 27 by shell-model calculations in sd-shell with the USDB Hamiltonian. Effects of Coulomb corrections on the rates are evaluated. The rates for pairs with A=23 and 25 are important for nuclear URCA processes that determine the cooling rate of O-Ne-Mg core, while those for pairs with A=20 and 24 are important for the core-contraction and heat generation rates in the core. We provide these nuclear rates at stellar environments in tables with fine enough meshes at various densities and temperatures for the studies of astrophysical processes sensitive to the rates. In particular, the accurate rate tables are crucially important for the final fates of not only O-Ne-Mg cores but also a wider range of stars such as C-O cores of lower mass stars.

    Comments:
    Accepted for publication in the Astrophysical Journal
    Subjects:
    Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
    arXiv:
    1512.00132 [pdf]
    ApJ(2016)·70 citations
  4. 08

    [Submitted on 1 Dec 2015] (cross-list from hep-lat)

    Hamiltonian effective field theory study of the resonance in lattice QCD

    Zhan-Wei Liu🇦🇺 · Waseem Kamleh🇦🇺 · Derek B. Leinweber🇦🇺 · Finn M. Stokes🇦🇺 · Anthony W. Thomas🇦🇺 · Jia-Jun Wu🇦🇺

    Drawing on experimental data for baryon resonances, Hamiltonian effective field theory (HEFT) is used to predict the positions of the finite-volume energy levels to be observed in lattice QCD simulations of the lowest-lying nucleon excitation. In the initial analysis, the phenomenological parameters of the Hamiltonian model are constrained by experiment and the finite-volume eigenstate energies are a prediction of the model. The agreement between HEFT predictions and lattice QCD results obtained on volumes with spatial lengths of 2 and 3 fm is excellent. These lattice results also admit a more conventional analysis where the low-energy coefficients are constrained by lattice QCD results, enabling a determination of resonance properties from lattice QCD itself. Finally, the role and importance of various components of the Hamiltonian model are examined.

    Comments:
    5 pages, 2 figures; version published in Phys. Rev. Lett
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1512.00140 [pdf]
    PRL(2016)·98 citations
  5. 09

    [Submitted on 1 Dec 2015] (cross-list from astro-ph.HE)

    Expected impact from weak reactions with light nuclei in core-collapse supernova simulations

    T. Fischer · G. Martínez-Pinedo · M. Hempel · L. Huther · G. Röpke · S. Typel · A. Lohs

    We study the role of light nuclear clusters in simulations of core-collapse supernovae. Expressions for the reaction rates are developed for a large selection of charged current absorption and scattering processes with light clusters. Medium modifications are taken into account at the mean-field level. We explore the possible impact on the supernova dynamics and the neutrino signal during the mass accretion phase prior to the possible explosion onset as well as during the subsequent protoneutron star deleptnoization after the explosion onset has been launched.

    Comments:
    7 pages, 3 figures, contribution to the OMEG 2015 conference proceedings, appears in EPJ WoC proceedings
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1512.00193 [pdf]
    EPJ Web Conf.(2016)·20 citations
  6. 10

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

    Particle production in high-energy collisions beyond the shockwave limit

    Tolga Altinoluk🇪🇸 · Adrian Dumitru🇺🇸

    We compute next to eikonal (NE) and next to next to eikonal (NNE) corrections to the Lipatov vertex due to a finite target thickness. These arise from electric field insertions into the eikonal Wilson lines. We then derive a -factorization formula for single inclusive gluon production at NNE accuracy and find that nuclear effects are absent. We also analyze NNE corrections to two-gluon production where some of the contributions are found to exhibit corrections proportional to .

    Comments:
    11 pages, 5 figures, corrected the result for the vertex, added derivation of two-gluon production cross section, published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1512.00279 [pdf]
    PRD(2016)·48 citations
  7. 11

    [Submitted on 25 Nov 2015] (cross-list from astro-ph.SR)

    Structures of the Vela pulsar and the glitch crisis from the Brueckner theory

    A. Li · J. M. Dong · J. B. Wang · R. X. Xu

    Detailed structures of the Vela pulsar (PSR B0833-45, with a period of milliseconds) are predicted by adopting a recently-constructed unified treatment of all parts of neutron stars: the outer crust, the inner crust and the core based on modern microscopic Brueckner-Hartree-Fock calculations. To take the pulsar mass ranging from to , we calculate the central density, the core/crust radii, the core/crust mass, the core/crustal thickness, the moment of inertia, and the crustal moment of inertia. Among them, the crustal moment of inertia could be effectively constrained from the accumulated glitch observations, which has been a great debate recently, known as "glitch crisis". Namely, superfluid neutrons contained in the inner crust, which are regarded as the origin of the glitch in the standard two-component model, could be largely entrained in the nuclei lattices, then there may not be enough superfluid neutrons ( less than the previous value) to trigger the large glitches () in the Vela pulsar. We then provide the first analysis of the crisis based on the microscopic basis, by confronting the glitch observations with the theoretical calculations for the crustal moment of inertia. We find that despite some recent opposition to the crisis argument, the glitch crisis is still present, which means that besides the crust superfluid neutrons, core neutrons might be necessary for explaining the large glitches of the Vela pulsar.

    Comments:
    28 pages, 6 figures, 4 tables
    Subjects:
    Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1512.00340 [pdf]
    Astrophys.J.Suppl.(2016)·38 citations

Affiliations

first authorsco-authorsvia INSPIRE