A measurement of lifetime differences in the neutral /D-meson system

Using a high statistics sample of photoproduced charm particles from the FOCUS experiment at Fermilab, we compare the lifetimes of neutral /D mesons decaying via D⁰-->K^-π⁺andK^- K⁺ to measure the lifetime differences between CP even and CP odd final states. These measurements bear on the phenomenology of D⁰-D¯⁰ mixing. If the D⁰-->K^-π⁺ is an equal mixture of CP even and CP odd eigenstates, we measure y_CP=(Γ(CPeven)- Γ(CPodd))/(Γ(CPeven)+Γ(CPodd))=0.0342+/-0.0139+/- 0.0074.