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arXiv · 2106.03875

Bayesian-Wilson coefficients in lattice QCD computations of valence PDFs and GPDs

Nikhil Karthik·Raza Sabbir Sufian
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Abstract

We propose an analysis method for the leading-twist operator product expansion based lattice QCD determinations of the valence parton distribution function (PDF). In the first step, we determine the confidence-intervals of the leading-twist $\overline{\mathrm{MS}}$ Wilson coefficients, $C_n(\mu^2 z^2)$, of the equal-time bilocal quark bilinear, given the lattice QCD matrix element of Ioffe-time distribution for a particular hadron $H$ as well as the prior knowledge of the valence PDF, $f(x,\mu)$ of the hadron $H$ determined via global fit from the experimental data. In the next step, we apply the numerically estimated $C_n$ in the lattice QCD determinations of the valence PDFs of other hadrons, and for the zero-skewness generalized parton distribution (GPD) of the same hadron $H$ at non-zero momentum transfers. Our proposal still assumes the dominance of leading-twist terms, but it offers a pragmatic alternative to the usage of perturbative Wilson coefficients and their associated higher-loop uncertainties such as the effect of all-order logarithms at larger sub-Fermi quark-antiquark separations $z$.

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Nikhil Karthik, Raza Sabbir Sufian. 2021-06-07. Bayesian-Wilson coefficients in lattice QCD computations of valence PDFs and GPDs. https://doi.org/10.1103/physrevd.104.074506

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