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Nuclear Theory·nucl-th

Wednesday·January 15, 2020

6 papers—4 primary·2 cross-listed

All6Primary4Cross-lists2
  1. 05

    [Submitted on 13 Jan 2020] (cross-list from hep-ph)

    Sub-femtometer scale color charge correlations in the proton

    Adrian Dumitru🇺🇸 · Vladimir Skokov🇺🇸 · Tomasz Stebel🇵🇱

    Color charge correlations in the proton at moderately small are extracted from its light-cone wave function. The charge fluctuations are far from Gaussian and they exhibit interesting dependence on impact parameter and on the relative transverse momentum (or distance) of the gluon probes. We provide initial conditions for small- Balitsky-Kovchegov evolution of the dipole scattering amplitude with impact parameter and dependence, and with non-zero -odd component due to three-gluon exchange. Lastly, we compute the (forward) Weizsaecker-Williams gluon distributions, including the distribution of linearly polarized gluons, up to fourth order in . The correction due to the quartic correlator provides a transverse momentum scale, GeV, for nearly maximal polarization.

    Comments:
    19 pages, 10 figures; tables of dipole scattering amplitude via two- and three-gluon exchange are available as ancillary files
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2001.04516 [pdf]
    PRD(2020)·23 citations
  2. 06

    [Submitted on 14 Jan 2020] (cross-list from hep-lat)

    Pion valence quark distribution from current-current correlation in lattice QCD

    Raza Sabbir Sufian🇺🇸 · Colin Egerer🇺🇸 · Joseph Karpie🇺🇸 · Robert G. Edwards🇺🇸 · Bálint Joó🇺🇸 · Yan-Qing Ma🇨🇳 · Kostas Orginos🇺🇸 · Jian-Wei Qiu🇺🇸 · David G. Richards🇺🇸

    We extract the pion valence quark distribution from lattice QCD (LQCD) calculated matrix elements of spacelike correlations of one vector and one axial vector current analyzed in terms of QCD collinear factorization, using a new short-distance matching coefficient calculated to one-loop accuracy. We derive the Ioffe time distribution of the two-current correlations in the physical limit by investigating the finite lattice spacing, volume, quark mass, and higher-twist dependencies in a simultaneous fit of matrix elements computed on four gauge ensembles. We find remarkable consistency between our extracted and that obtained from experimental data across the entire -range. Further, we demonstrate that the one-loop matching coefficient relating the LQCD matrix computed in position space to the in momentum space has well-controlled behavior with Ioffe time. This justifies that LQCD calculated current-current correlations are good observables for extracting partonic structures by using QCD factorization, which complements to the global effort to extract partonic structure from experimental data.

    Comments:
    Published version, Physical Review D
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2001.04960 [pdf]
    PRD(2020)·125 citations

Affiliations

first authorsco-authorsvia INSPIRE