Measurement of the B⁰ lifetime using partial reconstruction

Abstract

We present here the first measurement of the B0 lifetime using partial reconstruction in B0 → D*– ρ+ decay. A sample of approximately B0 → D*– ρ+ events were identified among 22.7 million BB pairs collected by the BABAR experiment during the years 1999-2000. With this data, the B0 lifetime is measured to be 1.616 ± 0.064 ± 0.075 ps. in good agreement with the world average. This measurement demonstrates that it is possible to use this technique to perform time-dependent B0 decay analysis that is central to the measurement of the charge-parity (CP) asymmetries. Investigation of CP observables through measurements of the decays of B0 mesons is the primary goal of the BABAR experiment at the PEP-II storage ring located at Stanford Linear Accelerator Center (SLAC). As the B0 particle decays to final states that are directly sensitive to the CP parameter γ are highly suppressed, a promising alternative approach is to use the final state B0 → D*h. Using the partial event reconstruction analysis method it is possible to compensate for the small CP asymmetries in this decay.