arXiv subjects
Publications and source records attributed to FOCUS Collaboration.
A precise determination of the charm-strange baryon Cascade(c)+ lifetime is presented. The data were accumulated by the Fermilab high-energy photoproduction experiment FOCUS. The measurement is made with 300 Cascade(c)+ --> Cascade- pi+ pi+ decays, 130 Cascade(c)+ --> Sigma+ K- pi+ decays, 45 Cascade(c)+ --> p K- pi+ decays and 58 Cascade(c)+ --> Lambda K- pi+ pi+ decays. The Cascade(c)+ lifetime is measured to be 0.439+/-0.022+/-0.009 ps.
We report on a direct measurement of the mixing parameter y=(3.42+-1.39+-0.74)% in the D0-D0bar system by measuring the lifetime difference between the CP mixed final state K^+pi^- and the CP even state K^+K^-. We also present a study of the decay \ws based on a sample of 149+-31 observed events compared to 36760+-195 events observed in the Cabibbo favored channel D0->K^-pi^+. The observed branching ratio R=(0.404+-0.085+-0.025)% is used to obtain limits on the mixing parameters x' and y' and the doubly Cabibbo suppressed branching ratio, R_DCS. These studies are based on a large sample of photoproduced charm mesons from the FOCUS experiment at Fermilab (FNAL-E831).
Using a large sample of photoproduced charm mesons from the FOCUS experiment at Fermilab (FNAL-E831), we observe the decay $D^0\to K^+π^-$ with a signal yield of $149\pm31$ events compared to a similarly cut sample consisting of $36760 \pm 195$ $D^0\to K^-π^+$ events. We use the observed ratio of $D^0\to K^+π^-$ to $D^0\to K^-π^+$ $(0.404\pm 0.085\pm 0.025)%$ to obtain a relationship between the $D^0$ mixing and doubly Cabibbo suppressed decay parameters.