ISSN:
1434-6052
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract A study ofB meson decays intoDl X final states is presented. In these events, neutral and chargedD mesons originate predominantly fromB + andB 0 decays, respectively. The dilution of this correlation due toD ** production has been taken into account. From 263 700 hadronicZ 0 decays collected in 1991 with the DELPHI detector at the LEP collider, 92D 0→K -π+, 35D +→K -π+π+ and 61D *0→D 0π+ followed byD 0→K -π+ orD 0→K -π+π+π-, are found with an associated lepton of the same charge as the kaon. From theD 0 l - andD *+ l -, the probabilityf d that ab quark hadronizes into aB − (or $$\bar B^0 $$ ) meson is found to be 0.44 ±0.08±0.09, corresponding to a total (B s+Λ b ) hadronization fraction of 0.12 −0.12 +0.24 . By reconstructing the energy of eachB meson, theb quark fragmentation is directly measured for the first time. The mean value of theB meson energy fraction is: $$\left\langle {X_E (B)} \right\rangle = 0.695 \pm 0.015(stat.) \pm 0.029(syst.)$$ ReconstructingD-lepton vertices, the followingB lifetimes are measured: $$\begin{gathered} \tau (B) = 1.27_{ - 0.18}^{ + 0.22} (stat.) \pm 0.15(syst.)ps, \hfill \\ where\bar B \to D^0 \ell ^ - X, \hfill \\ \tau (B) = 1.18_{ - 0.27}^{ + 0.39} (stat.) \pm 0.15(syst.)ps, \hfill \\ where\bar B \to D^ + \ell ^ - X, \hfill \\ \tau (B) = 1.19_{ - 0.19}^{ + 0.25} (stat.) \pm 0.15(syst.)ps \hfill \\ where\bar B \to D^{* + } \ell ^ - X, \hfill \\ \end{gathered} $$ and an average τ(B)=1.23 −0.13 +0.14 (stat.)±0.15(syst.) ps is found. Allowing for decays into $$D**\ell ^ - \bar v$$ , theB + andB 0 lifetimes are: $$\begin{gathered} \tau (B^ + ) = 1.30_{ - 0.29}^{ + 0.33} (stat.) \pm 0.15(syst.\exp .) \hfill \\ \pm 0.05(syst.D**)ps, \hfill \\ \tau (B^0 ) = 1.17_{ - 0.23}^{ + 0.29} (stat.) \pm 0.51(syst.\exp .) \hfill \\ \pm 0.05(syst.D**)ps, \hfill \\ \tau (B^ + )/\tau (B^0 ) = 1.11_{ - 0.39}^{ + 0.51} (stat.) \pm 0.05(syst.\exp .) \hfill \\ \pm 0.10(syst.D**)ps. \hfill \\ \end{gathered} $$
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01565048
