Dynamical Symmetry Breaking and the Sigma-Meson Mass in Quantum Chromodynamics

Abstract

The spontaneous breakdown of chiral symmetry is analyzed dynamically via bound-state Bethe-Salpeter equations. While in general spontaneous mass generation is linked to a massless $0^{-}$ pion and no specific constraint on a massive $0^{+}$ meson, for the particular theory of asymptotically free QCD it is shown that a $0^{+}$ $\sigma$ meson should exist with mass $m_{\sigma }\approx 600 \mathrm{to} 700$ MeV.