Measurement of b Hadron Lifetimes in Exclusive Decays Containing a J/Psi in p(p)over-bar Collisions at root s=1.96 TeV

We report on a measurement of b-hadron lifetimes in the fully reconstructed decay modes B{ sup+}{yields}J/{psi}K{ sup+}, B{ sup0}{yields}J/{psi}K{ sup*}(892){ sup0}, B{ sup0}{yields}J/{psi}K{sub s}{ sup0}, and {Lambda}{sub b}{ sup0}{yields}J/{psi}{Lambda}{ sup0} using data corresponding to an integrated luminosity of 4.3 fb{ sup-1}, collected by the CDF II detector at the Fermilab Tevatron. The measured lifetimes are {tau}(B{ sup+})=[1.639{+-}0.009( stat){+-}0.009(syst)] ps, {tau}(B{ sup0})=[1.507{+-}0.010( stat){+-}0.008(syst)] ps, and {tau}({Lambda}{sub b}{ sup0})=[1.537{+-}0.045( stat){+-}0.014(syst)] ps. The lifetime ratios are {tau}(B{ sup+})/{tau}(B{ sup0})=[1.088{+-}0.009( stat){+-}0.004(syst)] and {tau}({Lambda}{sub b}{ sup0})/{tau}(B{ sup0})=[1.020{+-}0.030( stat){+-}0.008(syst)]. These are the most precise determinations of these quantities from a single experiment.