Improved Measurement of the Probability for Gluon Splitting into b bbar in Z0 Decays

TL;DR

This paper reports a precise measurement of the gluon splitting rate into bottom quark pairs in Z0 decays, utilizing advanced vertex detection techniques to improve accuracy in identifying b quarks in hadronic events.

Contribution

The study introduces an improved measurement method for gluon splitting into b bbar in Z0 decays, leveraging upgraded CCD vertex detector technology for higher B-tagging efficiency.

Findings

Measured g -> b bbar rate as (2.44 ± 0.59 (stat) ± 0.34 (syst)) x 10^-3

Enhanced vertex detection technique improves identification of low-energy B hadrons

Provides more accurate data on gluon splitting into bottom quarks in Z0 decays.

Abstract

We have measured gluon splitting into bottom quarks, g -> b bbar, in hadronic Z0 decays collected by SLD between 1996 and 1998. The analysis was performed by looking for secondary bottom production in 4-jet events of any primary flavor. 4-jet events were identified, and in each event a topological vertex-mass technique was applied to the two jets closest in angle in order to identify them as b or bbar jets. The upgraded CCD vertex detector gives very high B-tagging efficiency, especially for B hadrons with the low energies typical of this process. We measured the rate of g -> b bbar production per hadronic event, g_bb, to be (2.44+-0.59 (stat) +-0.34 (syst)) X10**-3.