Lightlike Wilson loops and gauge invariance of Yang-Mills theory in 1+1 dimensions.

Light–like Wilson loops and gauge invariance of Yang–Mills theory in 1+1 dimensions Abstract A light-like Wilson loop is computed in perturbation theory up to O(g 4) for pure Yang–Mills theory in 1+1 dimensions, using Feynman and light–cone gauges to check its gauge invariance. After dimensional regularization in intermediate steps, a finite gauge invariant result is obtained, which however does not exhibit abelian exponentiation. Our result is at variance with the common belief that pure Yang– Mills theory is free in 1+1 dimensions, apart perhaps from topological effects.