ANALYTIC STRUCTURE OF HEAVY-QUARK PROPAGATORS

The renormalized quark Dyson-Schwinger equation is studied in the limi t of the renormalized current heavy quark mass m(R)-->infinity. We are particularly interested in the analytic pole structure of the heavy q uark propagator in the complex momentum plane. Approximations in which the quark-gluon vertex is modelled by either the bare vestex or the B all-Chiu Ansatz and the Landau gauge gluon propagator takes either a G aussian form or a Gaussian form with an ultraviolet asymptotic tail ar e used. [S0556-2821(98)00303-8].