On the Transition from Confinement to Screening in QCD_{1+1} Coupled to Adjoint Fermions at Finite N

TL;DR

This paper investigates the transition from confinement to screening in finite-N SU(N) QCD in 1+1 dimensions with adjoint fermions, providing numerical evidence that stable constituent particles form at any N, not just in the large-N limit.

Contribution

It demonstrates that the confinement-to-screening transition occurs at finite N, extending previous large-N results and analyzing topological properties of the spectrum.

Findings

Stable constituent particles form at finite N.

Transition occurs at zero fermion mass for any N.

Discussion of topological features in the spectrum.

Abstract

We consider SU(N) QCD_{1+1} coupled to massless adjoint Majorana fermions, where N is finite but arbitrary. We examine the spectrum for various values of N, paying particular attention to the formation of multi-particle states, which were recently identified by Gross, Hashimoto and Klebanov in the N -> infinity limit of the theory. It is believed that in the limit of vanishing fermion mass, there is a transition from confinement to screening in which string-like states made out of adjoint fermion bits dissociate into stable constituent ``single particles''. In this work, we provide numerical evidence that such a transition into stable constituent particles occurs not only at large N, but for any finite value of N. In addition, we discuss certain issues concerning the ``topological'' properties exhibited by the DLCQ spectrum.