Measurement of the Bc± Meson Lifetime Using Bc±->J/ψ+l±+X Decays

This thesis describes a measurement of the average proper decay time of the B±c mesons, the ground state of bottom and charm quark bound states. The lifetime measurement is carried out in the decay modes B±c -> J/ψ+e±+X and B±c -> J/ψ+μ±+X, where the J/ψ decays as J/ψ -> μ+μ- and the X are unmeasured particles such as νe or νμ. The data are collect by the CDF II detector which measures the properties of particles created in sqrt(s)=1.96 TeV proton/antiproton collisions delivered by the Fermilab Tevatron. This measurement uses ~fb-1 of integrated luminosity. The measured average proper decay time of B±c mesons, τ = 0.475+0.053-0.049(stat.)±0.018(syst.) ps, is competitive with the most precise measurements in the world and confirms previous measurements and theoretical predictions