Computability of GPDs near x=±ξ in Lattice QCD
Abstract
In lattice QCD computations of generalized parton distributions (GPDs), the large momentum expansion generally requires all hard scales, 2|x±ξ|Pz and 2|1± x|Pz, to be much larger than ΛQCD. We show that this condition can be relaxed for 2|x±ξ|Pz at large ξ, making the important x∼±ξ regions accessible to lattice calculations and considerably expanding the region of computability. Revisiting previous lattice results with complete one-loop matching, we obtain the expected partonic threshold behavior---GPDs continuous at x=±ξ but with discontinuous derivatives---which has not previously been observed on the lattice. We thus obtain, for the first time, important prediction for GPDs in the distribution-amplitude-like region, which smoothly connects the quark and antiquark PDF-like behaviors.
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BibTeX
@misc{su2026computability,
title = {{Computability of GPDs near $x=\pmξ$ in Lattice QCD}},
author = {Yushan Su and Xiangdong Ji and Yizhuang Liu and Rui Zhang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.20545},
eprint = {2609.20545},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.20545},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Computability of GPDs near x=±ξ in Lattice QCD
AU - Yushan Su
AU - Xiangdong Ji
AU - Yizhuang Liu
AU - Rui Zhang
PY - 2026
DA - 2026/09/17
PB - arXiv
DO - 10.48550/arxiv.2609.20545
UR - https://arxiv.org/abs/2609.20545
AB - In lattice QCD computations of generalized parton distributions (GPDs), the large momentum expansion generally requires all hard scales, 2|x±ξ|P^z and 2|1± x|P^z, to be much larger than Λ_QCD. We show that this condition can be relaxed for 2|x±ξ|P^z at large ξ, making the important x∼±ξ regions accessible to lattice calculations and considerably expanding the region of computability. Revisiting previous lattice results with complete one-loop matching, we obtain the expected partonic threshold behavior---GPDs continuous at x=±ξ but with discontinuous derivatives---which has not previously been observed on the lattice. We thus obtain, for the first time, important prediction for GPDs in the distribution-amplitude-like region, which smoothly connects the quark and antiquark PDF-like behaviors.
ER -