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Nuclear Theory·nucl-th

Thursday·October 5, 2017

6 papers—1 primary·5 cross-listed

All6Primary1Cross-lists5
  1. 02

    [Submitted on 4 Oct 2017] (cross-list from hep-lat)

    Pion decay in magnetic fields

    Gunnar S. Bali🇩🇪 · Bastian B. Brandt🇩🇪 · Gergely Endrodi🇩🇪 · Benjamin Glaessle🇩🇪

    The leptonic decay of the charged pion in the presence of background magnetic fields is investigated using quenched Wilson fermions. It is demonstrated that the magnetic field opens up a new channel for this decay. The magnetic field-dependence of the decay constants for both the ordinary and the new channel is determined. Using these inputs from QCD, we calculate the total decay rate perturbatively.

    Comments:
    8 pages, 6 figures, talk presented at the 35th International Symposium on Lattice Field Theory, 18-24 June 2017, Granada, Spain
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1710.01502 [pdf]
    EPJ Web Conf.(2018)·6 citations
  2. 03

    [Submitted on 4 Oct 2017] (cross-list from astro-ph.IM)

    Bayesian estimation of thermonuclear reaction rates for deuterium+deuterium reactions

    Á. Gómez Iñesta🇪🇸 · C. Iliadis🇺🇸 · A. Coc🇫🇷

    The study of d+d reactions is of major interest since their reaction rates affect the predicted abundances of D, 3He, and 7Li. In particular, recent measurements of primordial D/H ratios call for reduced uncertainties in the theoretical abundances predicted by big bang nucleosynthesis (BBN). Different authors have studied reactions involved in BBN by incorporating new experimental data and a careful treatment of systematic and probabilistic uncertainties. To analyze the experimental data, Coc et al. (2015) used results of ab initio models for the theoretical calculation of the energy dependence of S-factors in conjunction with traditional statistical methods based on Chi-2 minimization. Bayesian methods have now spread to many scientific fields and provide numerous advantages in data analysis. Astrophysical S-factors and reaction rates using Bayesian statistics were calculated by Iliadis et al. (2016). Here we present a similar analysis for two d+d reactions, d(d,n)3He and d(d,p)3H, that has been translated into a total decrease of the predicted D/H value by 0.16%.

    Comments:
    To appear in the Astrophysical Journal
    Subjects:
    Instrumentation and Methods for Astrophysics (astro-ph.IM); Nuclear Theory (nucl-th)
    arXiv:
    1710.01647 [pdf]
    ApJ(2017)·39 citations
  3. 04

    [Submitted on 4 Oct 2017] (cross-list from hep-ph)

    Investigating the Transverse Single Spin Asymmetry in the Inelastic photoproduction in and collisions

    V. P. Goncalves🇧🇷

    In this paper we propose to investigate the transverse single spin asymmetry in the inelastic photoproduction in and collisions at RHIC energies. At leading order this process probes the gluon Sivers function. We predict large values for the cross sections, which indicates that its experimental analysis is, in principle, feasible. The rapidity dependence of the single spin asymmetry is presented. We obtain that the asymmetry is strongly dependent on the model used for the gluon Sivers function and that it can be probed by the analysis of the production at forward rapidities. Our results indicate that a future experimental analysis of this process can be useful to constrain the gluon Sivers function.

    Comments:
    7 pages, 2 figures, 1 table. Improved version to be published in Physical Review D
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1710.01674 [pdf]
    PRD(2018)·7 citations
  4. 05

    [Submitted on 4 Oct 2017] (cross-list from hep-ph)

    Pinning down the linearly-polarised gluons inside unpolarised protons using quarkonium-pair production at the LHC

    Jean-Philippe Lansberg🇫🇷 · Cristian Pisano🇮🇹 · Florent Scarpa🇫🇷 · Marc Schlegel🇩🇪

    We show that the production of J/psi or Upsilon pairs in unpolarised pp collisions is currently the best process to measure the momentum-distribution of linearly-polarised gluons inside unpolarised protons through the study of azimuthal asymmetries. Not only the short-distance coefficients for such reactions induce the largest possible cos 4 phi modulations, but analysed data are already available. Among the various final states previously studied in unpolarised pp collisions within the TMD factorisation approach, di-J/psi production exhibits by far the largest asymmetries, up to 50% in the region studied by the ATLAS and CMS experiments. In addition, we use the very recent LHCb data at 13 TeV to perform the first fit of the unpolarised transverse-momentum-dependent gluon distribution.

    Comments:
    v2: 8 pages, 7 figures, uses LaTeX with elsarticle. v2 matches the published version in PLB up to a numerical mistake and mislabellings in Figs. 4 which are the object of a submitted corrigendum
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1710.01684 [pdf]
    PLB(2018)·94 citations
  5. 06

    [Submitted on 4 Oct 2017] (cross-list from physics.data-an)

    A New Correlator to Detect and Characterize the Chiral Magnetic Effect

    Niseem Magdy (1) · Shuzhe Shi (2) · Jinfeng Liao (2) · N. Ajitanand (1) · Roy A. Lacey (1) ((1) Department of Chemistry, State University of New York, Stony Brook, New York, (2) Physics Department and Center for Exploration of Energy and Matter, Indiana University, IN)

    A charge-sensitive in-event correlator is proposed and tested for its efficacy to detect and characterize charge separation associated with the Chiral Magnetic Effect (CME) in heavy ion collisions. Tests, performed with the aid of two reaction models, indicate discernible responses for background- and CME-driven charge separation, relative to the second- () and third-order () event planes, which could serve to identify the CME. The tests also indicate a degree of sensitivity which would enable robust characterization of the CME via Anomalous Viscous Fluid Dynamics (AVFD) model comparisons.

    Comments:
    5 pages, 5 Figs.; Published version
    Subjects:
    Data Analysis, Statistics and Probability (physics.data-an); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1710.01717 [pdf]
    PRC(2018)·72 citations

Affiliations

first authorsco-authorsvia INSPIRE