Mass spectrum and elastic scattering in the massive SU(2)_f Schwinger model on the lattice

Abstract

We calculate numerically scattering phases for elastic meson-meson scattering processes in the strongly coupled massive Schwinger-model with an SU(2) flavour symmetry. These calculations are based on Luescher's method in which finite size effects in two-particle energies are exploited. The results from Monte-Carlo simulations with staggered fermions for the lightest meson ("pion") are in good agreement with the analytical strong-coupling prediction. Furthermore, the mass spectrum of low-lying mesonic states is investigated numerically. We find a surprisingly rich spectrum in the mass region [m_π,4 m_π].