String formation and chiral symmetry breaking in the heavy-light   quark-antiquark system in QCD
  The effective quark Lagrangian is written for a light quark in the field of a static antiquark, explicitly containing field correlators as coefficient functions of products of quark operators. At large N_c the closed system of equations for the gauge-invariant quark Green's function in the field of static source is examined analytically. The formation of the string connecting the light quark to the static source is observed numerically. The scalar Lorentz nature of the resulting confinement is shown to hold for the considered case, implying chiral symmetry breaking. The resulting spectrum with and without perturbative gluon exchanges is obtained numerically and compared to the B and D meson masses and HQET. 
Yu.A. Simonov (ITEP,Moscow, Russia), J.A. Tjon (ITP,U. Utrecht,The   Netherlands)