Upper limit on the lifetime difference of short- and long-lived B0s mesons

An upper limit on the lifetime difference of short- and long-lived B0s mesons has been obtained using an inclusive bottom hadron sample from 2 million hadronic Z decays collected by the L3 experiment at LEP. A lifetime fit has been performed on data samples separately enriched in neutral and charged b hadrons. An experimental upper limit on the decay rate difference of short- and long-lived B0s mesons of (|ΔΓ|/Γ)B0s<0.67 (95% C.L.) has been determined. In addition, the lifetimes of B+ and B0d mesons have been measured to be τ(B+)=1.66±0.06±0.03ps and τ(B0d)=1.52±0.06±0.04ps, where the first errors are statistical and the second are systematic.