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

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 b̄-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 Ēb+ and Ω̄b+ baryons gives the production fraction of B+ mesons: fBu = (40.99 ± 0.82(stat) ± 1.11(syst))%. © 2003 Elsevier B.V. All rights reserved.