The Spectrum of a Large N Gauge Theory Near Transition from Confinement to Screening

TL;DR

This paper investigates how the spectrum of a 1+1D large N QCD model with an adjoint fermion changes near the transition from confinement to screening, showing the spectrum becomes continuous above a critical mass.

Contribution

It provides numerical evidence and theoretical analysis of the spectrum transition in large N QCD with adjoint fermions near the confinement-screening boundary.

Findings

Spectrum becomes continuous above a critical mass

Critical mass equals twice the lightest bound state mass

Numerical DLCQ results support the theoretical prediction

Abstract

We study the spectrum of 1+1 dimensional large $N$ QCD coupled to an adjoint Majorana fermion of mass $m$. As $m\to 0$ this model makes a transition from confinement to screening. We argue that in this limit the spectrum becomes continuous for mass greater than twice the mass of the lightest bound state. This critical mass is nothing but the threshold for a decay into two lightest states. We present numerical results based on DLCQ that appear to support our claim.