Measurement of the Lifetime of the $B_c^{\pm}$ Meson Using Semileptonic Decays

We report on a measurment of the lifetime of the $B_c^{\pm}$ meson using the semileptonic decay modes $B_c^{\pm} \rightarrow J/\psi \ell^{\pm} X$ with $J/\psi \rightarrow \mu^+ \mu^-$. The measurement utilizes 1~fb$^{-1}$ of data collected with the CDF\,II detector during Run\,II of the Fermilab Tevatron in $p\bar{p}$ collisions at $\sqrt{s} = 1.96$~TeV. The measurement combines the $J/\psi\mu^{\pm}$ and $J/\psi e^{\pm}$ final states in a single framework to increase the statistical reach of the data while minimizing systematic differences between the two final states.