Probing nucleon strange and charm distributions with lattice QCD

Abstract

We present the first lattice-QCD calculation of the unpolarized strange and charm parton distribution functions using large-momentum effective theory (LaMET). We use a lattice ensemble with 2+1+1 flavors of highly improved staggered quarks (HISQ) generated by MILC collaboration, with lattice spacing $a\approx 0.12$ fm and $M_{\pi }\approx 310$ MeV, and clover valence fermions with two valence pion masses: 310 and 690 MeV. We use momentum-smeared sources to improve the signal up to nucleon boost momentum $P_z=2.18$ GeV, and determine nonperturbative renormalization factors in RI/MOM scheme. We compare our lattice results with the matrix elements obtained from matching the PDFs from CT18NNLO and NNPDF3.1NNLO global fits. Our data support the assumptions of strange-antistrange and charm-anticharm symmetry that are commonly used in global PDF fits, and we find smaller than expected parton distribution at mid to small $x$.

7 pages, 10 figures

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Cited by in corpus (11)

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• Parton distributions and lattice QCD calculations: toward 3D structure
• Lattice continuum-limit study of nucleon quasi-PDFs
• The persistent nonperturbative charm enigma
• First Glimpse into the Kaon Gluon Parton Distribution Using Lattice QCD
• Gluon Parton Distribution of the Nucleon from 2+1+1-Flavor Lattice QCD in the Physical-Continuum Limit
• One-Loop Hybrid Renormalization Matching Kernels for Quasi-Parton Distributions
• Non-singlet quark helicity PDFs of the nucleon from pseudo-distributions
• Impact of Lattice Strangeness Asymmetry Data in the CTEQ-TEA Global Analysis
• Theoretical tools for neutrino scattering: interplay between lattice QCD, EFTs, nuclear physics, phenomenology, and neutrino event generators
• Light-cone PDFs and GPDs from Lattice QCD