On the low-energy spectrum of an SU(2) gauge theory with dynamical fermions

TL;DR

This paper investigates the low-energy spectrum of an SU(2) gauge theory with dynamical fermions using advanced Bethe-Salpeter equations, revealing notable differences from SU(3) theories but less than some lattice studies suggest.

Contribution

It applies a beyond rainbow-ladder truncation with a self-consistent fermion-gauge-boson vertex to study the spectrum, providing new insights into SU(2) gauge theories.

Findings

Differences observed compared to SU(3) meson spectrum.

Less pronounced differences than some lattice studies.

Use of a 3PI-type truncation approach.

Abstract

The spectrum of light bound states in an SU(2) gauge theory with two flavors of fundamentally charged fermions is investigated by solving the Bethe-Salpeter equations in the respective channels within a 3PI-type (i.e., beyond rainbow-ladder) truncation including self-consistently a correspondingly truncated fermion--gauge-boson vertex. Remarkable differences with respect to the meson spectrum of an SU(3) gauge theory are found although in our approach these are not as pronounced as indicated by some recent respective investigations within lattice gauge field theory.