Meson spectrum in $QCD_2$ revisited

TL;DR

This paper revisits the meson spectrum in two-dimensional QCD, incorporating new Lorentz-invariant terms and a gluon mass regulator, finding these modifications do not alter the original spectrum results.

Contribution

It introduces a novel class of Lorentz-invariant terms in the 't Hooft model and explores the effects of a gluon mass regulator on the meson spectrum.

Findings

New Lorentz-invariant terms do not affect the meson spectrum.

Gluon mass regulator recovers the original 't Hooft results when set to zero.

The model's spectrum remains consistent under the introduced modifications.

Abstract

Recently it has been shown that in two dimensions is possible to add new Lorentz invariant terms built with fractions containing the null vector $n= (1, 1)$. In this work, we have computed the meson spectrum following the 't Hooft model in $QCD_2$ incorporating these new kinds of terms. We found these new terms does not affect the meson spectrum. We have computed the 't Hooft model with a new regulator. We have introduced a gluon mass and we have recovered the 't Hooft result when this parameter is set to zero.