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A Measurement of B meson production and lifetime using D lepton- events in Z0 decays

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Abreu, P. [--] Cortina Gil, Eduardo [UCL] DELPHI Collaboration [--]

A study of B 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 Bˉ0 ) 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: ⟨XE(B)⟩=0.695±0.015(stat.)±0.029(syst.) Reconstructing D-lepton vertices, the followingB lifetimes are measured: τ(B)=1.27+0.22−0.18(stat.)±0.15(syst.)ps,hfillwhereBˉ→D0ℓ−X,hfillτ(B)=1.18+0.39−0.27(stat.)±0.15(syst.)ps,hfillwhereBˉ→D+ℓ−X,hfillτ(B)=1.19+0.25−0.19(stat.)±0.15(syst.)pshfillwhereBˉ→D∗+ℓ−X,hfill and an average τ(B)=1.23 −0.13 +0.14 (stat.)±0.15(syst.) ps is found. Allowing for decays into D∗∗ℓ−vˉ , theB + andB 0 lifetimes are: τ(B+)=1.30+0.33−0.29(stat.)±0.15(syst.exp.)hfill±0.05(syst.D∗∗)ps,hfillτ(B0)=1.17+0.29−0.23(stat.)±0.51(syst.exp.)hfill±0.05(syst.D∗∗)ps,hfillτ(B+)/τ(B0)=1.11+0.51−0.39(stat.)±0.05(syst.exp.)hfill±0.10(syst.D∗∗)ps.hfill

Document type Article de périodique (Journal article) – Article de recherche
Access type Accès libre
Publication date 1993
Language Anglais
Journal information "Zeitschrift für Physik. C, Particles and fields" - Vol. 57, no.2, p. 181-196 (1993)
Publisher Springer (Berlin)
issn 0170-9739
e-issn 1431-5858
Publication status Publié
Affiliation UCL - SST/IRMP - Institut de recherche en mathématique et physique
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Bibliographic reference Abreu, P. ; Cortina Gil, Eduardo ; DELPHI Collaboration ; et. al. A Measurement of B meson production and lifetime using D lepton- events in Z0 decays . In: Zeitschrift für Physik. C, Particles and fields, Vol. 57, no.2, p. 181-196 (1993)
Permanent URL http://hdl.handle.net/2078.1/127228