Journal of High Energy Physics (Nov 2021)

Towards high-precision parton distributions from lattice QCD via distillation

  • Colin Egerer,
  • Robert G. Edwards,
  • Christos Kallidonis,
  • Kostas Orginos,
  • Anatoly V. Radyushkin,
  • David G. Richards,
  • Eloy Romero,
  • Savvas Zafeiropoulos,
  • on behalf of the HadStruc collaboration

DOI
https://doi.org/10.1007/JHEP11(2021)148
Journal volume & issue
Vol. 2021, no. 11
pp. 1 – 49

Abstract

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Abstract We apply the Distillation spatial smearing program to the extraction of the unpolarized isovector valence PDF of the nucleon. The improved volume sampling and control of excited-states afforded by distillation leads to a dramatically improved determination of the requisite Ioffe-time Pseudo-distribution (pITD). The impact of higher-twist effects is subsequently explored by extending the Wilson line length present in our non-local operators to one half the spatial extent of the lattice ensemble considered. The valence PDF is extracted by analyzing both the matched Ioffe-time Distribution (ITD), as well as a direct matching of the pITD to the PDF. Through development of a novel prescription to obtain the PDF from the pITD, we establish a concerning deviation of the pITD from the expected DGLAP evolution of the pseudo-PDF. The presence of DGLAP evolution is observed once more following introduction of a discretization term into the PDF extractions. Observance and correction of this discrepancy further highlights the utility of distillation in such structure studies.

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