Eur. Phys. J. C (2015) 75: 100
https://doi.org/10.1140/epjc/s10052-015-3324-x

Regular Article - Theoretical Physics

Hadronic bound states in SU(2) from Dyson–Schwinger equations

¹ Institut für Physik, Karl-Franzens–Universität Graz, Universitätsplatz 5, 8010, Graz, Austria
² Institut für Theoretische Physik, Justus-Liebig–Universität Giessen, 35392, Giessen, Germany

^* e-mail: milan.vujinovic@uni-graz.at

Received: 9 December 2014
Accepted: 17 February 2015
Published online: 28 February 2015

Abstract

By using the Dyson–Schwinger/Bethe–Salpeter formalism in Euclidean spacetime, we calculate the ground state spectrum of hadrons in an SU(2) gauge theory with two fundamental fermions. We show that the rainbow-ladder truncation, commonly employed in QCD studies, is unsuitable for a description of an SU(2) theory. This we remedy by truncating at the level of the quark–gluon vertex Dyson–Schwinger equation in a diagrammatic expansion. Results obtained within this novel approach show good agreement with lattice studies. These findings emphasize the need to use techniques more sophisticated than rainbow-ladder when investigating generic strongly interacting gauge theories.