Role of Resonances in Heavy Meson Processes within Standard Model and Beyond

The effective theory based on combined chiral and heavy quark symmetry, the heavy meson chiral perturbation theory, is applied to studying the role of resonances in various processes of heavy mesons within and beyond the Standard Model. Chiral corrections including both positive and negative parity heavy meson doublets are calculated to the effective strong couplings featuring in the effective theory leading order interaction Lagrangian, to the Isgur-Wise functions in semileptonic B to D decays and to the complete set of supersymmetric four-quark operators mediating heavy neutral meson mixing. Bare values of the effective strong couplings are extracted from the measured decay widths of charmed resonances. Chiral behavior of the couplings, Isgur-Wise functions and heavy meson bag parameters is studied in the leading logarithmic approximation. In semileptonic heavy to light decays we determine resonance contributions to the various form factors within an effective theory inspired model at zero recoil. We employ a form factor parameterization based on effective theory limits to extrapolate our results to the whole kinematical region in charm decays. We compare our results with experimental data and lattice calculations. Very rare nonleptonic decays of the B_c meson are studied within the Standard Model where they are mediated by box loop diagrams, and within a number of Standard Model extensions. Based on existing experimental searches for related B meson decays, limits are imposed on some of the models studied. The most promissing nonleptonic two- and three-body decay channels of the B_c meson in the search for such new physics contributions are identified.