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arXiv · 2606.29597

Complete Access to Leading-Twist $\Lambda$-Baryon Light-Cone Distribution Amplitudes from Lattice QCD

Mu-Hua Zhang·Haoyang Bai·Min-Huan Chu·Jun Hua·Xiangdong Ji·Xiangyu Jiang·Jian Liang·Cai-Dian Lü·Andreas Schäfer·Wei Wang·Yi-Bo Yang·Jian-Hui Zhang·Jia-Lu Zhang·Qi-An Zhang
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Abstract

We report the first complete lattice-QCD determination of the leading-twist light-cone distribution amplitudes (LCDAs) of the $\Lambda$ baryon, obtained as full two-dimensional functions of the valence-quark momentum fractions. The calculation employs large-momentum effective theory to relate the light-cone amplitudes to equal-time nonlocal three-quark matrix elements of boosted $\Lambda$ baryons. Controlled physical extrapolations to the continuum, physical pion mass, and infinite momentum, together with hybrid renormalization, large-$\lambda$ extrapolation, and perturbative matching, yield the three leading-twist LCDAs $V$, $A$, and $T$. Using the lattice-determined LCDAs in place of the asymptotic form, we find an $\mathcal{O}(10\%)$ shift in the $\Lambda$ electromagnetic form factor at perturbative scales, demonstrating that the full two-dimensional LCDAs, rather than only their asymptotic shapes or lowest moments, are required for precision baryonic phenomenology. This work, together with the companion paper [1] detailing the baryon-LaMET framework, provides the first complete multi-dimensional $x$-dependent baryon LCDAs from first principles and establishes a benchmark for lattice access to multi-dimensional baryon structure.

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Mu-Hua Zhang, Haoyang Bai, Min-Huan Chu, Jun Hua, Xiangdong Ji, Xiangyu Jiang, Jian Liang, Cai-Dian Lü, Andreas Schäfer, Wei Wang, Yi-Bo Yang, Jian-Hui Zhang, Jia-Lu Zhang, Qi-An Zhang. 2026-06-28. Complete Access to Leading-Twist $\Lambda$-Baryon Light-Cone Distribution Amplitudes from Lattice QCD. https://arxiv.org/abs/2606.29597

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