Speaker
Description
Within the framework of Landau-gauge QCD, we investigate the causal structure of fundamental propagators and evaluate their impact on physical observables, such as decay widths. Focusing on the light-quark sector, we present a self-consistent calculation of the quark spectral function obtained by solving the Dyson-Schwinger (gap) equation within a causal Rainbow-Ladder approximation. By systematically mapping the influence of infrared interaction strength on the propagator’s analytic structure, we demonstrate that the first singularity remains real across all investigated coupling strengths. Furthermore, we identify a critical vertex strength that triggers the emergence of additional complex-conjugate poles. We elucidate the mechanism driving the formation of these poles within the Rainbow-Ladder framework and discuss its fundamental connection to Dynamical Chiral Symmetry Breaking (DCSB).