Work

Pion Distribution Amplitudes from Functional QCD

Year: 2026

Type: preprint

Abstract: We present the first functional QCD calculation of the pion distribution amplitude (DA) using the large-momentum effective theory within the functional renormalisation group (fRG) approach. With only the strong coupling and current quark masses as inputs, we compute the quasi-DA from first-principles QCD correlation functions. By pushing the pion momentum up to $P_z = 4.5\ \mathrm{GeV}$, the quasi-DA becomes fully saturated, rendering the extrapolation errors to the light-cone limit negligible. The resulting second-order moment $\langle ξ^2 \rangle_π= 0.267$ is significantly smaller than existing lattice-LaMET determinations and lies in a range consistent with other nonperturbative approaches.

Source: arXiv (Cornell University)

DOI: 10.48550/arxiv.2607.04871

Authors: Chang, Lei, Fu, Wei-jie, Huang, Chuang, Pawlowski, Jan M., Tan, Yang-yang

Institutions: Nankai University, Dalian University of Technology, Heidelberg University, GSI Helmholtz Centre for Heavy Ion Research, ExtreMe Matter Institute EMMI, RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences, The University of Tokyo

Topic: Quantum Chromodynamics and Particle Interactions

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: Deutsche Forschungsgemeinschaft, National Natural Science Foundation of China, Chinese Academy of Sciences, Emberi Eroforrások Minisztériuma, Japan Society for the Promotion of Science

Awards: G1170463422, G1620761618, G6191194835, G6526081583, G6705375793, G6952224768, EXC 2181: STRUKTUREN: Emergenz in Natur, Mathematik und komplexen Daten, SFB 1225: Isolierte Quantensysteme und Universalität unter extremen Bedingungen (ISOQUANT)

OpenAlex ID: W7167587285

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