Measurement of the B0 meson lifetime with partial reconstruction of B0 --> D*- pi+ and B0 --> D*- rho+ decays

Abstract

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 ${\mathrm{fb}}^{-1}$. The decays $B^0\to D^{\ast -}{\pi }^{+}$ and $B^0\to D^{\ast -}{\rho }^{+}$ 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 $1.533\pm 0.034(stat.)\pm 0.038(syst.)\mathrm{ps}$. This measurement serves as a test and validation of procedures required to measure the CP violation parameter $\sin (2\beta +\gamma )$ with partial reconstruction of these modes.

8 pages, 2 encapsulated postscript figues