Measurement of the B0bar Lifetime and of the B0-B0bar Oscillation Frequency Using Partially Reconstructed B0bar -> D*+ l- anti-nu(l) Decays

TL;DR

This paper reports a precise measurement of the B0 meson lifetime and oscillation frequency using a large sample of partially reconstructed decays in the BABAR experiment, providing key parameters for understanding B meson behavior.

Contribution

It presents the first simultaneous measurement of B0 lifetime and mixing parameter using partially reconstructed decays at BABAR, with improved precision over previous results.

Findings

B0 lifetime measured as 1.501 ps with small uncertainties.

B0-B0bar oscillation frequency determined as 0.523 ps^{-1}.

Results are consistent with Standard Model predictions.

Abstract

We present a simultaneous measurement of the B0bar lifetime tau(B0) and mixing parameter $Delta m_d$. We use a sample of about 50000 B0bar -> D*+ l- anti-nu(l) partially reconstructed decays identified with the BABAR detector at the PEP-II storage ring at SLAC, where the flavor of the other B meson is determined from the charge of another high momentum lepton in the same event. The preliminary results are: tau(B0) = (1.501+/-0.008(stat.) +/- 0.030 (syst.)) ps, $Delta m_d$ = (0.523+/-0.004(stat.) +/- 0.007 (syst.)) ps^{-1}.