Dynamical gluon effects in twist-3 generalized parton distributions of the proton
Abstract
Within the Basis Light-Front Quantization framework, we systematically investigate the subleading-twist (twist-3) generalized parton distributions (GPDs) of the proton's valence quarks beyond the Wandzura--Wilczek (WW) approximation. The twist-3 GPDs are not independent; through the equations of motion they decompose into a non-genuine contribution and a genuine twist-3 term. The latter encodes quark--quark--gluon correlations and involves interference between the light-front Fock sectors |qqq> and |qqqg>, which are typically neglected in the WW approximation. Using light-front wave functions obtained from diagonalizing the proton light-front Hamiltonian for its |qqq> and |qqqg> Fock components, we compute these GPDs via their overlap representations. To further explore their physical implications, we also evaluate several twist-3--related quantities, including the quark orbital angular momentum, the total quark spin contribution, and the quark spin--orbit correlation. Our results provide new nonperturbative input on higher-twist dynamics particularly multi-parton interference effects relevant for future measurements at the EicC and the EIC.
Keywords
Cite
@article{arxiv.2601.07590,
title = {Dynamical gluon effects in twist-3 generalized parton distributions of the proton},
author = {Ziqi Zhang and Chandan Mondal and Siqi Xu and Xingbo Zhao and James P. Vary},
journal= {arXiv preprint arXiv:2601.07590},
year = {2026}
}