Transversity PDFs of the proton from lattice QCD with physical quark masses

Author:

Xiang Gao, Andrew D. Hanlon, Swagato Mukherjee, Peter Petreczky, Qi Shi, Sergey Syritsyn, Yong Zhao

Keyword:

High Energy Physics - Lattice, 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)

journal:

date:

2023-10-28 16:00:00

Abstract

We present a lattice QCD calculation of the transversity isovector- and isoscalar-quark parton distribution functions (PDFs) of the proton utilizing a perturbative matching at next-to-leading-order (NLO) accuracy. Additionally, we determine the isovector and isoscalar tensor charges for the proton. In both calculations, the disconnected contributions to the isoscalar matrix elements have been ignored. The calculations are performed using a single ensemble of $N_f = 2 +1$ highly-improved staggered quarks simulated with physical-mass quarks and a lattice spacing of $a = 0.076$ fm. The Wilson-clover action, with physical quark masses and smeared gauge links obtained from one iteration of hypercubic (HYP) smearing, is used in the valence sector. Using the NLO operator product expansion, we extract the lowest four to six Mellin moments and the PDFs from the matrix elements via a neural network. In addition, we calculate the $x$-dependence of the PDFs with hybrid-scheme renormalization and the recently developed leading-renormalon resummation technique, at NLO with the resummation of leading small-$x$ logarithms.

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