Semileptonic Lifetimes of B Mesons from CDF RUN II Data

A measurement of the B+/-, B0, and Bs mesons' lifetimes are presented using semileptonic decay from $\sim$ 350 pb-1 of data collected by CDF's lepton plus displaced track trigger. The decays of B$\rightarrow$l nu DX, where D is either D0, D*, Ds, are partially reconstructed from a lepton, a displaced track, and a fully reconstructed charm meson. The B+/-, B0, and Bs lifetimes are obtained from an unbinned maximum-likelihood fit to the proper decay length distribution.