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Nuclear Theory·nucl-th

Wednesday·June 10, 2015

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 01

    [Submitted on 8 Jun 2015]

    Estimate of the theoretical uncertainty of the cross sections for nucleon knockout in neutral-current neutrino-oxygen interactions

    Artur M. Ankowski🇺🇸 · Maria B. Barbaro🇮🇹 · Omar Benhar🇺🇸 · Juan A. Caballero🇪🇸 · Carlotta Giusti🇮🇹 · Raúl González-Jiménez🇪🇸 · Guillermo D. Megias🇪🇸 · Andrea Meucci🇮🇹

    Free nucleons propagating in water are known to produce gamma rays, which form a background to the searches for diffuse supernova neutrinos and sterile neutrinos carried out with Cherenkov detectors. As a consequence, the process of nucleon knockout induced by neutral-current quasielastic interactions of atmospheric (anti)neutrinos with oxygen needs to be under control at the quantitative level in the background simulations of the ongoing and future experiments. In this paper, we provide a quantitative assessment of the uncertainty associated with the theoretical description of the nuclear cross sections, estimating it from the discrepancies between the predictions of different models.

    Comments:
    7 pages, 2 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1506.02673 [pdf]
    PRC(2015)·11 citations
  2. 02

    [Submitted on 9 Jun 2015]

    The torque effect and fluctuations of entropy deposition in rapidity in ultra-relativistic nuclear collisions

    Piotr Bozek🇵🇱 · Wojciech Broniowski🇵🇱

    The decorrelation of the orientation of the event-plane angles in the initial state of relativistic Pb-Pb and p-Pb collisions, the "torque effect," is studied in a model of entropy deposition in the longitudinal direction involving fluctuations of the longitudinal source profile on large scales. The radiation from a single wounded nucleon is asymmetric in space-time rapidity. It is assumed that the extent in rapidity of the region of deposited entropy is random. Fluctuations in the deposition of entropy from each source increase the event-plane decorrelation: for Pb-Pb collisions they improve the description of the data, while for p-Pb collisions the mechanism is absolutely essential to generate any sizable decorrelation. We also show that the experimental data for rank-four flow may be explained via folding of the elliptic flow. The results suggest the existence of long range fluctuations in the space-time distribution of entropy in the initial stages of relativistic nuclear collisions.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1506.02817 [pdf]
    PLB(2016)·75 citations
  3. 03

    [Submitted on 9 Jun 2015]

    Quantifying jet transport properties via large hadron production

    Zhi-Quan Liu🇨🇳 · Hanzhong Zhang🇨🇳 · Ben-Wei Zhang🇨🇳 · Enke Wang🇨🇳

    Nuclear modification factor for large single hadron is studied in a next-to-leading order (NLO) perturbative QCD (pQCD) parton model with medium-modified fragmentation functions (mFFs) due to jet quenching in high-energy heavy-ion collisions. The energy loss of the hard partons in the QGP is incorporated in the mFFs which utilize two most important parameters to characterize the transport properties of the hard parton jets: the jet transport parameter and the mean free path , both at the initial time . A phenomenological study of the experimental data for is performed to constrain the two parameters with simultaneous fits to RHIC as well as LHC data. We obtain for energetic quarks GeV/fm and fm in central collisions at GeV, while GeV/fm, and fm in central collisions at TeV. Numerical analysis shows that the best fit favors a multiple scattering picture for the energetic jets propagating through the bulk medium, with a moderate averaged number of gluon emissions. Based on the best constraints for and , the estimated value for the mean-squared transverse momentum broadening is moderate which implies that the hard jets go through the medium with small reflection.

    Comments:
    8 pages, 6 figures, revised version
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1506.02840 [pdf]
    EPJC(2016)·41 citations
  4. 04

    [Submitted on 3 Jun 2015] (cross-list from physics.atom-ph)

    Theory of the n=2 levels in muonic deuterium

    Julian J. Krauth · Marc Diepold · Beatrice Franke · Aldo Antognini · Franz Kottmann · Randolf Pohl

    The present knowledge of Lamb shift, fine- and hyperfine structure of the and states in muonic deuterium is reviewed in anticipation of the results of a first measurement of several transition frequencies in muonic deuterium (). A term-by-term comparison of all available sources reveals reliable values and uncertainties of the QED and nuclear structure-dependent contributions to the Lamb shift, which are essential for a determination of the deuteron rms charge radius from . Apparent discrepancies between different sources are resolved, in particular for the difficult two-photon exchange contributions. Problematic single-sourced terms are identified which require independent recalculation.

    Comments:
    26 pages, add missing feynman diagrams (Fig. 3), renumber items (Tab. IV), correct a sum (column 5, Tab. IV)
    Subjects:
    Atomic Physics (physics.atom-ph); Nuclear Theory (nucl-th)
    arXiv:
    1506.01298 [pdf]
    Annals Phys.(2016)·76 citations
  5. 05

    [Submitted on 8 Jun 2015] (cross-list from hep-ph)

    Proof of NRQCD Factorization at All Order in Coupling Constant in Heavy Quarkonium Production

    Gouranga C. Nayak🇺🇸

    Recently the proof of factorization in heavy quarkonium production in NRQCD color octet mechanism is given at next-to-next-to-leading order (NNLO) in coupling constant by using diagrammatic method of QCD. In this paper we prove factorization in heavy quarkonium production in NRQCD color octet mechanism at all order in coupling constant by using path integral method of QCD. Our proof is valid to all powers in the heavy quark relative velocity. We find that the gauge invariance and the factorization at all order in coupling constant require gauge-completed non-perturbative NRQCD matrix elements that were introduced previously to prove factorization at NNLO.

    Comments:
    Final Version, Accepted for Publication in Eur. Phys. J. C, 37 Pages Latex
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    1506.02593 [pdf]
    EPJC(2016)·37 citations
  6. 06

    [Submitted on 8 Jun 2015] (cross-list from hep-ph)

    Two photon exchange amplitude with \pi N intermediate states: spin-1/2 and spin-3/2 channels

    Dmitry Borisyuk🇺🇦 · Alexander Kobushkin🇺🇦

    We calculate two-photon exchange (TPE) amplitudes for the elastic electron-proton scattering, and take into account intermediate hadronic states containing \pi N system with total angular momentum 1/2 or 3/2, which includes 8 different channels. This is the improvement of our previous calculation, where only the \pi N states with quantum numbers of \Delta(1232) resonance were included. The results show good consistency with recent experimental data. At high Q^2, newly-calculated contributions affect the correction to the measured proton form factor ratio \mu G_E/G_M. The total correction becomes somewhat smaller compared to our previous work, but is still significant and grows approximately linearly with Q^2. Comparing contributions of different channels, we found that larger contributions come from the channels with quantum numbers of lightest resonances.

    Comments:
    6 pages, 6 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1506.02682 [pdf]
    PRC(2015)·32 citations
  7. 07

    [Submitted on 9 Jun 2015] (cross-list from hep-ph)

    Generalized perturbations in neutrino mixing

    Jiajun Liao🇺🇸 · D. Marfatia🇺🇸 · K. Whisnant🇺🇸

    We derive expressions for the neutrino mixing parameters that result from complex perturbations on (1) the Majorana neutrino mass matrix (in the basis of charged lepton mass eigenstates) and on (2) the charged lepton mass matrix, for arbitrary initial (unperturbed) mixing matrices. In the first case, we find that the phases of the elements of the perturbation matrix, and the initial values of the Dirac and Majorana phases, strongly impact the leading order corrections to the neutrino mixing parameters and phases. For experimentally compatible scenarios wherein the initial neutrino mass matrix has symmetry, we find that the Dirac phase can take any value under small perturbations. Similarly, in the second case, perturbations to the charged lepton mass matrix can generate large corrections to the mixing angles and phases of the PMNS matrix. As an illustration of our generalized procedure, we apply it to a situation in which nonstandard scalar and nonstandard vector interactions simultaneously affect neutrino oscillations.

    Comments:
    26 pages, 3 figures, 1 table. Published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1506.03013 [pdf]
    PRD(2015)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE