TBA equations for excited states

by Balog, Janos

Abstract

TBA integral equations describing the finite volume dependence of the mass gap are proposed for the sausage- and SS-models and their $\sigma$-model limits (the $O(3)$ and $O(4)$ nonlinear $\sigma$-models, respectively). The results are compared with Monte Carlo measurements and (for small volumes) 3-loop perturbation theory.