A measurement of the branching fractions of the b-quark into charged and neutral b-hadrons

TL;DR

This paper measures the production fractions of charged and neutral b-hadrons in Z0 decays using a neural network-based algorithm to identify b-hadron charge, providing precise estimates of B+ meson production.

Contribution

It introduces a neural network algorithm to estimate b-hadron charge and measures their production fractions in Z0 decay events.

Findings

Charged b-hadron production fraction: 42.09%

B+ meson production fraction: 41.00%

Method achieves high statistical and systematic precision

Abstract

The production fractions of charged and neutral b-hadrons in b-quark events from Z0 decays have been measured with the DELPHI detector at LEP. An algorithm has been developed, based on a neural network, to estimate the charge of the weakly-decaying b-hadron by distinguishing its decay products from particles produced at the primary vertex. From the data taken in the years 1994 and 1995, the fraction of bbar-quarks fragmenting into positively charged weakly-decaying b-hadrons has been measured to be: f^+ = (42.09 +/- 0.82 (stat.) +/- 0.89 (syst.))%. Subtracting the rates for charged Xibar_b^+ and Omegabar_b^+ baryons gives the production fraction of B^+ mesons: f_Bu = (40.99 +/- 0.82 (stat.) +/- 1.11 (syst.))%.