Heavy-light quark systems from the QCD instanton vacuum: Nf =1 light flavor case

We investigate heavy-light quark systems within the framework of the QCD instanton vacuum, focusing on the Nf = 1 light flavor case. We derive an effective heavy-light quark interaction from the low-energy QCD partition function and construct a heavy-meson effective Lagrangian. The physical residual mass of heavy mesons, Lambda, is determined by employing compositeness and normalization conditions. We calculate the masses of D and B mesons and their weak decay constants to the leading order and next-to-leading order in the 1/mQ expansion. The current results for fD and fB are in good agreement with recent lattice QCD data and Particle Data Group (PDG) average values.