Unpolarized proton PDF at NNLO from lattice QCD with physical quark masses

Abstract

We present a lattice QCD calculation of the unpolarized isovector quark parton distribution function (PDF) of the proton utilizing a perturbative matching at next-to-next-to-leading-order (NNLO). The calculations are carried out using a single ensemble of gauge configurations generated with $N_f=2+1$ highly-improved staggered quarks with physical masses and a lattice spacing of $a=0.076$ fm. We use one iteration of hypercubic smearing on these gauge configurations, and the resulting smeared configurations are then used for all aspects of the subsequent calculation. For the valence quarks, we use the Wilson-clover action with physical quark masses. We consider several methods for extracting information on the PDF. We first extract the lowest four Mellin moments using the leading-twist operator product expansion approximation. Then, we determine the $x$ dependence of the PDF through a deep neural network within the pseudo-PDF approach and additionally through the framework of large-momentum effective theory utilizing a hybrid renormalization scheme. This is the first application of the NNLO matching coefficients for the nucleon directly at the physical point.

20 pages, 17 figures, and 3 tables; version accepted for publication in PRD

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Cited by in corpus (17)

• Threshold resummation for computing large-$x$ parton distribution through large-momentum effective theory
• Pion Valence Quark Distribution at Physical Pion mass of $N_f=2+1+1$ Lattice QCD
• Moments of parton distribution functions of any order from lattice QCD
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• Generalized parton distributions from the pseudo-distribution approach on the lattice
• Nucleon Helicity Parton Distribution Function in the Continuum Limit with Self-Renormalization
• Light Cone Distribution Amplitude for the $\Lambda$ Baryon from Lattice QCD
• Mapping Parton Distributions of Hadrons with Lattice QCD
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• Valence Quark PDFs of the Proton from Two-Current Correlations in Lattice QCD
• Large-Momentum Effective Theory's Asymptotic Extrapolation vs the Inverse Problem
• Generalized Parton Distributions from Lattice QCD with Asymmetric Momentum Transfer: Unpolarized Quarks at Nonzero Skewness
• Moments from Momentum Derivatives in Lattice QCD
• Renormalon effect of quasi-PDF in gradient flow formalism
• Global Analyses of Generalized Parton Distributions with Diverse PDF Inputs
• Lattice QCD Benchmark of Proton Helicity and Flavor-Dependent Unpolarized Transverse Momentum-Dependent Parton Distribution Functions at Physical Quark Masses
• QCD analysis of valence structure functions using deep inelastic lepton-nucleon scattering