D Physics

Abstract

Recently a lot of new experimental results on open charm hadrons have appeared. In particular many D meson resonances have been discovered. We discuss strong decays of positive and negative parity charmed mesons within heavy meson chiral perturbation theory and study the impact of excited charm states on the determination of the effective meson couplings. Motivated by recent experimental results we also reconsider semileptonic D to P l nu and D to V l nu decays within a model which combines heavy quark symmetry and properties of the chiral Lagrangian. Using limits of soft collinear effective theory and heavy quark effective theory we parametrize the semileptonic form factors. We include excited charm meson states in our Lagrangians and determine their impact on the charm meson semileptonic form factors. In some scenarios of new physics an up-like heavy quark appears, which induces FCNC at tree level for the c to u Z transitions. We investigate FCNC effects in D rare decays in particular the c to u l+ l- transition which might occur in D+ to pi+ l+ l- and D0 to rho0 l+ l-.