Measurement of the ${\mathit{B}}^0$ and ${\mathit{B}}^{+}$ Meson Lifetimes with Fully Reconstructed Hadronic Final States

The $B^0$ and $B^{+}$ meson lifetimes have been measured in $e^{+}{e}^{-}$ annihilation data collected in 1999 and 2000 with the BABAR detector at center-of-mass energies near the $\Upsilon \left(4S\right)$ resonance. Events are selected in which one B meson is fully reconstructed in a hadronic final state while the second B meson is reconstructed inclusively. A combined fit to the $B^0$ and the $B^{+}$ decay time difference distributions yields ${\tau }_{B^0}=1.546\mathrm{}\pm 0.032\left(\mathrm{stat}\right)\pm 0.022\left(\mathrm{syst}\right)\mathrm{ps}$, ${\tau }_{B^{+}}=1.673\mathrm{}\pm 0.032\left(\mathrm{stat}\right)\pm 0.023\left(\mathrm{syst}\right)\mathrm{ps}$, and ${\tau }_{B^{+}}/{\tau }_{B^0}=1.082\mathrm{}\pm 0.026\left(\mathrm{stat}\right)\pm 0.012\left(\mathrm{syst}\right)$.