Measurement of the B+ and B0 Lifetimes from Semileptonic Decays

TL;DR

This paper reports precise measurements of B+ and B0 meson lifetimes using semileptonic decay data from Z0 decays, employing a novel vertexing method to reconstruct decay lengths and charges.

Contribution

It introduces a new vertexing technique for semileptonic B decays that improves lifetime measurement accuracy in Z0 decay data.

Findings

Measured B+ lifetime as 1.61 ps

Measured B0 lifetime as 1.56 ps

B+ and B0 lifetimes are consistent within uncertainties

Abstract

The lifetimes of B+ and B0 mesons are measured using a sample of 150,000 hadronic Z0 decays collected by the SLD experiment at the SLC between 1993 and 1995. The analysis identifies the semileptonic decays of B mesons and reconstructs the B meson decay length and charge by vertexing the lepton with a partially reconstructed D meson. This new method results in a sample of 634 (584) charged (neutral) decays with high charge purity. The ratio of B+ : B0 decays in the charged (neutral) sample is 3:1 (1:3). A maximum likelihood fit yields t(B+) = 1.61 +0.13 -0.12(stat) +/- 0.07(syst) ps, t(B0) = 1.56 +0.14 -0.13(stat) +/- 0.10(syst) ps, and t(B+)/t(B0) = 1.03 +0.16 -0.14(stat) +/- 0.09(syst).