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

TL;DR

This paper measures the B0 meson lifetime using partial reconstruction of specific decay modes with data from the BaBar detector, providing a precise lifetime value and validating techniques for CP violation studies.

Contribution

It introduces a partial-reconstruction method to measure B0 lifetime with high precision, aiding future CP violation measurements.

Findings

B0 lifetime measured as 1.533 ps with uncertainties

Sample sizes of approximately 7000 and 5500 events

Validation of partial reconstruction techniques for CP studies

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 ${\rm fb}^{-1}$. 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 {\rm (stat.)} \pm 0.038 {\rm (syst.)} {\rm 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.