Light-front field theory of hot and dense quark matter

Extending the concepts of light-front field theory to quantum statistics provides a novel approach towards nuclear matter under extreme conditions. Such conditions exist, e.g., in neutron stars or in the early stage of our universe. They are experimentally expected to occur in heavy ion collisions, e.g., at RHIC and accelerators to be build at GSI and CERN. Light-front field theory is particularly suited, since it is based on a relativistic Hamiltonian approach. It allows us to treat the perturbative as well as the nonperturbative regime of QCD and also correlations that emerge as a field of few-body physics and is important for hadronization. Last but not least the Hamiltonian approach is useful for nonequilibrium processes by utilizing, e.g., the formalism of nonequilibrium statistical operators.Comment: 6 pages, talk presented at Light-Cone 2004, Amsterdam, 16 - 20 Augus

Quark Structure and Weak Decays of Heavy Mesons

We investigate the quark structure of D and B mesons in the framework of a constituent quark model. To this end, we assume a scalar confining and a one gluon exchange (OGE) potential. The parameters of the model are adopted to reproduce the meson mass spectrum. From a fit to ARGUS and CLEO data on B->D*lv semileptonic decay we find for the Cabbibo Kobayashi Maskawa matrix element Vcb=0.036+-0.003. We compare our form factors to the pole dominance hypothesis and the heavy quark limit. For non-leptonic decays we utilize factorization and for B->D*X decays we find a1 = 0.96+-0.05, and a2=0.31+-0.03.Comment: LATEX, 26 pages, 12 tables, 6 figures (appended as uuencoded file but also available as postscript files from the authors), BONN TK-93-1