In gauge-free quark models, quasi-PDFs converge to PDFs with proven sum rules, and the Covariant Parton Model supplies closed-form small-x results that match a Wandzura-Wilczek approximation for the quark energy-momentum tensor form factor.
A complete non-perturbative renormalization prescription for quasi-PDFs
6 Pith papers cite this work. Polarity classification is still indexing.
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Pith papers citing it
abstract
In this work we present, for the first time, the non-perturbative renormalization for the unpolarized, helicity and transversity quasi-PDFs, in an RI' scheme. The proposed prescription addresses simultaneously all aspects of renormalization: logarithmic divergences, finite renormalization as well as the linear divergence which is present in the matrix elements of fermion operators with Wilson lines. Furthermore, for the case of the unpolarized quasi-PDFs, we describe how to eliminate the unwanted mixing with the twist-3 scalar operator. We utilize perturbation theory for the one-loop conversion factor that brings the renormalization functions to the MS-scheme at a scale of 2 GeV. We also explain how to improve the estimates on the renormalization functions by eliminating lattice artifacts. The latter can be computed in one-loop perturbation theory and to all orders in the lattice spacing. We apply the methodology for the renormalization to an ensemble of twisted mass fermions with Nf=2+1+1 dynamical light quarks, and a pion mass of around 375 MeV.
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First lattice QCD results for Mellin moments of pion and kaon unpolarized PDFs from nonlocal operator matrix elements on a 32^3×64 twisted-mass ensemble at m_π=260 MeV, extracted at NNLO and μ=2 GeV.
Lattice QCD calculation of pion and kaon unpolarized quark PDFs on a 32^3×64 ensemble with 260 MeV pion mass, using LaMET and SDF matching at boosts up to 2.07 GeV.
Analysis of non-perturbative lattice data shows that the inverse problem in LaMET introduces significant uncertainties in parton distributions, especially from harmonics around λ=5-15, and that exact asymptotic decay matters little in the currently applicable x range.
Renormalized matrix elements for the unpolarized quasi-PDF of the Δ⁺ are computed on two N_f=2+1+1 twisted mass lattice ensembles with pion masses 250 and 330 MeV using momentum smearing.
Reanalysis of lattice data produces proton u(x)-d(x) PDF consistent with global fits within 1 sigma, supporting large-momentum expansion for PDF predictions.
citing papers explorer
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Quasi Parton Distribution Functions in Covariant Quark Models
In gauge-free quark models, quasi-PDFs converge to PDFs with proven sum rules, and the Covariant Parton Model supplies closed-form small-x results that match a Wandzura-Wilczek approximation for the quark energy-momentum tensor form factor.
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Mellin Moments of Pion and Kaon Unpolarized PDFs from Nonlocal Operators in Lattice QCD
First lattice QCD results for Mellin moments of pion and kaon unpolarized PDFs from nonlocal operator matrix elements on a 32^3×64 twisted-mass ensemble at m_π=260 MeV, extracted at NNLO and μ=2 GeV.
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Pion and Kaon PDFs from Lattice QCD via Large Momentum Effective Theory and Short-Distance Factorization
Lattice QCD calculation of pion and kaon unpolarized quark PDFs on a 32^3×64 ensemble with 260 MeV pion mass, using LaMET and SDF matching at boosts up to 2.07 GeV.
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Inverse problem in the LaMET framework
Analysis of non-perturbative lattice data shows that the inverse problem in LaMET introduces significant uncertainties in parton distributions, especially from harmonics around λ=5-15, and that exact asymptotic decay matters little in the currently applicable x range.
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Parton distribution functions of $\Delta^+$ on the lattice
Renormalized matrix elements for the unpolarized quasi-PDF of the Δ⁺ are computed on two N_f=2+1+1 twisted mass lattice ensembles with pion masses 250 and 330 MeV using momentum smearing.
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Proton's isovector PDF with updated analysis of large-momentum lattice data
Reanalysis of lattice data produces proton u(x)-d(x) PDF consistent with global fits within 1 sigma, supporting large-momentum expansion for PDF predictions.