A Systematic Study of the Decays of Charmed D Mesons

Citation

Hauser, Jay (1985) A Systematic Study of the Decays of Charmed D Mesons. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/g0wf-ny80. https://resolver.caltech.edu/CaltechTHESIS:01312019-122402912

Abstract

A large sample of D mesons, produced by the decay of the Ψ(3770) and observed by the Mark III detector at SPEAR, forms the basis for a study of the decays of charmed D⁺ and D⁰ mesons. Many Cabibbo-allowed and Cabibbo-suppressed decays are observed. When normalized by a new, absolute technique, the branching ratios appear significantly higher than those reported by previous experiments. No evidence is found for specific final states from D⁰ decay which are indicative of non-spectator W-exchange diagrams: limits are quoted. Finally, the inclusive semileptonic branching fractions of charged and neutral D mesons are measured by observation of electrons in the recoil from fully reconstructed hadronic D decays of known charm. By neglecting the contribution of Cabibbo-suppressed decays to the total decay widths, the ratio of these branching fractions can be interpreted as the ratio of D⁺ and D⁰ lifetimes, thus confirming the inequality of lifetimes observed by direct decay length experiments. The observed pattern of hadronic decays appears to favor modification of the spectator model over non-spectator processes as the main source of the lifetime difference.

Thesis Files