| Özet: | A study of B meson decays into DlX final states is presented. In these events, neutral and charged D mesons originate predominantly from B+ and B0 decays, respectively. The dilution of this correlation due to D** production has been taken into account. From 263 700 hadronic Z0 decays collected in 1991 with the DELPHI detector at the LEP collider, 92 D0→K-π+, 35 D+→K-π+π+ and 61 D*0→D0π+ followed by D0→K-π+ or D0→K-π+π+π -, are found with an associated lepton of the same charge as the kaon. From the D0l- and D*+l-, the probability fd that a b quark hadronizes into a B- (or {Mathematical expression}) meson is found to be 0.44 ±0.08±0.09, corresponding to a total (Bs+Λb) hadronization fraction of 0.12-0.12+0.24. By reconstructing the energy of each B meson, the b quark fragmentation is directly measured for the first time. The mean value of the B meson energy fraction is: {Mathematical expression} Reconstructing D-lepton vertices, the following B lifetimes are measured: {Mathematical expression} and an average τ(B)=1.23-0.13+0.14(stat.)±0.15(syst.) ps is found. Allowing for decays into {Mathematical expression}, the B+ and B0 lifetimes are: {Mathematical expression} © 1993 Springer-Verlag.
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