Measurement of B0 - B0-bar flavor oscillations using jet-charge and lepton flavor tagging in p p-bar collisions at sqrt[s]=1.8 TeV

Abstract

We present a measurement of the mass difference Delta m_d for the B0 meson and the statistical power of the b flavor tagging methods used. The measurement uses 90 (1/pb) of data from p p-bar collisions at sqrt[s] = 1.8 TeV collected with the CDF detector. An inclusive lepton trigger is used to collect a large sample of B hadron semileptonic decays. The mass difference Delta m_d is determined from the proper time dependence of the fraction of B hadrons that undergo flavor oscillations. The flavor at decay is inferred from the charge of the lepton from semileptonic B decay. The initial flavor is inferred by determining the flavor of the other B hadron produced in the collision, either from its semileptonic decay (soft-lepton tag) or from its jet charge. The measurement yields Delta m_d = 0.500 +/- 0.052 +/- 0.043 hbar/ps, where the first uncertainty is statistical and the second uncertainty is systematic. The statistical powers (epsilon D^2) of the soft-lepton and jet-charge flavor taggers are (0.91 +/- 0.10 +/- 0.11) % and (0.78 +/- 0.12 +/- 0.08) %, respectively.