Simultaneous measurement of the B^0 meson lifetime and mixing frequency with B^0→D*−l+ν_ℓ decays
We measure the B^0 lifetime τ_B^0 and the B0−B0[overbar] oscillation frequency Δm_d with a sample of approximately 14000 exclusively reconstructed B^0→D*−ℓ+ν_l signal events, selected from 23 million BB[overbar] pairs recorded at the Υ(4S) resonance with the BABAR detector at the Stanford Linear Accelerator Center. The decay position of the other B is determined with the remaining tracks in the event, and its b-quark flavor at the time of decay is determined with a tagging algorithm that exploits the correlation between the flavor of the b quark and the charges of its decay products. The lifetime and oscillation frequencies are measured simultaneously with an unbinned maximum-likelihood fit that uses, for each event, the measured difference in decay times of the two B mesons (Δt), the calculated uncertainty on Δt, the signal and background probabilities, and b-quark tagging information for the other B. The results are τ_B^0=(1.523^(+0.024)_(−0.023)±0.022)ps and Δm_d=(0.492±0.018±0.013)ps^(−1). The statistical correlation coefficient between τ_B0 and Δm_d is -0.22.
Additional Information© 2003 American Physical Society. Received 5 December 2002; published 24 April 2003. We are grateful for the extraordinary contributions of our PEP-II colleagues in achieving the excellent luminosity and machine conditions that have made this work possible. The success of this project also relies critically on the expertise and dedication of the computing organizations that support BABAR. The collaborating institutions wish to thank SLAC for its support and the kind hospitality extended to them. This work is supported by the U.S. Department of Energy and National Science Foundation, the Natural Sciences and Engineering Research Council (Canada), Institute of High Energy Physics (China), the Commissariat à l'Energie Atomique and Institut National de Physique Nucléaire et de Physique des Particules (France), the Bundesministerium für Bildung und Forschung and Deutsche Forschungsgemeinschaft (Germany), the Istituto Nazionale di Fisica Nucleare (Italy), the Research Council of Norway, the Ministry of Science and Technology of the Russian Federation, and the Particle Physics and Astronomy Research Council (United Kingdom). Individuals have received support from the A. P. Sloan Foundation, the Research Corporation, and the Alexander von Humboldt Foundation.
Published - PhysRevD.67.072002.pdf