Analytic properties of the Landau gauge gluon and quark propagators

R. Alkofer, W. Detmold, C. S. Fischer, P. Maris
2004 Physical Review D  
We explore the analytic structure of the gluon and quark propagators of Landau gauge QCD from numerical solutions of the coupled system of renormalized Dyson--Schwinger equations and from fits to lattice data. We find sizable negative norm contributions in the transverse gluon propagator indicating the absence of the transverse gluon from the physical spectrum. A simple analytic structure for the gluon propagator is proposed. For the quark propagator we find evidence for a mass-like singularity
more » ... ss-like singularity on the real timelike momentum axis, with a mass of 350 to 500 MeV. Within the employed Green's functions approach we identify a crucial term in the quark-gluon vertex that leads to a positive definite Schwinger function for the quark propagator.
doi:10.1103/physrevd.70.014014 fatcat:zlmx6rbuozhl5jeoa6pucvpybe