Measurement of theB0meson lifetime with partial reconstruction ofB0→D*−π+andB0→D*−ρ+decays

The neutral B meson lifetime is measured with the data collected by the BABAR detector at the PEP-II storage ring during the years 1999 and 2000, with a total integrated luminosity of 20.7 ${\mathrm{fb}}^{\mathrm{-}1}$. The decays $B^0\to D^{*-}{\pi }^{+}$ and $B^0\to D^{*-}{\rho }^{+}$ are selected with a partial-reconstruction technique, yielding samples of $6970\pm 240$ and $5520\pm 250$ signal events, respectively. With these events, the $B^0$ lifetime is measured to be $1.533\pm 0.034\left(\mathrm{stat}\right)\pm 0.038\left(\mathrm{syst}\right)\mathrm{ps}.$ This measurement serves as a test and validation of procedures required to measure the CP violation parameter $\sin (2\mathrm{}\beta +\gamma )$ with partial reconstruction of these modes.