Baryon Bethe-Salpeter Equation in Minkowski-Space QCD$_2$
Abstract
We study the three-quark ladder Bethe--Salpeter equation in Minkowski-space QCD in the light-cone gauge. Using the quasi-potential expansion, we project the baryon equation onto the light front and show that, at leading order in the valence truncation, the resulting mass-squared eigenvalue equation is equivalent to the Bars--Durgut equation. We also derive the endpoint power-law behavior of the valence wave function in terms of the quark mass and coupling, closely paralleling the original 't Hooft analysis for mesons. The resulting three-quark equation is solved numerically for , and the ground-state baryon mass is found to be in reasonable agreement with previous light-cone quantization results in QCD, suggesting that the valence sector provides the dominant contribution to the ground state. The excited-state spectrum further yields a Regge trajectory that captures the overall trend of the experimental nucleon spectrum, and we compute selected structure observables, including parton distribution functions, double distribution amplitudes, and coordinate-space densities. This framework provides a useful confining test bed for Minkowski-space bound-state methods and for future developments toward confining formulations in 3+1 dimensions beyond the valence truncation.
Cite
@article{arxiv.2605.07095,
title = {Baryon Bethe-Salpeter Equation in Minkowski-Space QCD$_2$},
author = {Satvir Kaur and Sreeraj Nair and Chandan Mondal and Jiangshan Lan and Xingbo Zhao and J. P. B. C. de Melo and Tobias Frederico},
journal= {arXiv preprint arXiv:2605.07095},
year = {2026}
}
Comments
11 pages, 7 figures