Towards finding the single-particle content of two-dimensional adjoint QCD

TL;DR

This paper investigates the single-particle spectrum of two-dimensional adjoint QCD by comparing approximations and analyzing eigenfunctions, revealing conditions under which multi-particle states are absent and exploring the structure of single-particle states.

Contribution

It introduces a method to distinguish single-particle states in 2D adjoint QCD by comparing asymptotic and approximate theories, highlighting the absence of multi-particle states under certain conditions.

Findings

Multi-particle states are absent when pair production is disallowed.

Hints of a double Regge trajectory for single-particle states.

Bosonic single-particle states do not form multi-particle states.

Abstract

The single-particle content of two-dimensional adjoint QCD remains elusive due to the inability to distinguish single- from multi-particle states. To find a criterion we compare several approximations to the theory. Starting from the asymptotic theory (no pair production, only singular operators), we construct sets of eigenfunctions in the lowest parton sectors of the theory. A perturbative treatment of the omitted operators is performed. We find that multi-particle states are absent if pair-production is disallowed and hints for a double Regge trajectory of single-particle states. We discuss the structure of the eigensystem of the theory, and present the reason for the fact that bosonic single-particle states do not form multi-particle states.