Mass structure of hadrons and light-front sum rules in t' Hooft model

TL;DR

This paper investigates the internal mass and energy distribution of hadrons in the two-dimensional t' Hooft model, deriving light-front sum rules and analyzing form factors to deepen understanding of hadronic structure in simplified QCD.

Contribution

It introduces new light-front sum rules for scalar charge and Coulomb energy in the t' Hooft model, relating them to wave functions and mass structure analysis.

Findings

Masses relate to scalar charge and Coulomb energy matrix elements.

Sum rules are regular at zero momentum fraction without delta functions.

Results include analysis of the massless Goldstone boson and gravitational form factors.

Abstract

We study the mass/energy structure of the bound state of hadrons in two-dimensional quantum chromodynamics in the large number of color limit (t' Hooft model). We analyze separately the contributions from the traceless and trace part of the energy-momentum tensor, and show that the masses are related to the matrix elements of the scalar charge and Coulomb energy. We derive the light-front sum rules for the scalar charge and Coulomb energy, expressed in terms of the light-front wave functions, and find that they are regular at $x=0$ without the delta function contribution. We also consider the result for the massless Goldstone boson, as well as the structure of the gravitational form factors of the bound meson states.