We have used the CLEO II detector to study the multiplicity of charged particles in the decays of B mesons produced at the $\Upsilon(4S)$ resonance. Using a sample of 1.5 x 10^6 B meson pairs, we find the mean inclusive charged particle multiplicity to be 10.71 +- 0.02 +0.21/-0.15 for the decay of the pair. This corresponds to a mean multiplicity of 5.36 +- 0.01 +0.11/-0.08 for a single B meson. Using the same data sample, we have also extracted the mean multiplicities in semileptonic and nonleptonic decays. We measure a mean of 7.82 +- 0.05 +0.21/-0.19 charged particles per $B\bar{B}$ decay when both mesons decay semileptonically. When neither B meson decays semileptonically, we measure a mean charged particle multiplicity of 11.62 +- 0.04 +0.24/-0.18 per $B\bar{B}$ pair.
Charged track multiplicity (i.e. charged hadron and charged lepton) in B meson decay.
Using data collected with the CLEO II detector at the Cornell Electron Storage Ring, we determine the ratio R(chrg) for the mean charged multiplicity observed in Upsilon(1S)->gggamma events, to the mean charged multiplicity observed in e+e- -> qqbar gamma events. We find R(chrg)=1.04+/-0.02+/-0.05 for jet-jet masses less than 7 GeV.
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The charged multiplicity has been measured at the ϒ(4S) and a value of 5.75±0.1±0.2 has been obtained for the mean charged multiplicity in B-meson decay. Combining this result with the measurement of prompt leptons from B decay, the values 4.1±0.35±0.2 and 6.3±0.2±0.2 are found for the semileptonic and nonleptonic charged multiplicities, respectively. If b→c dominance is assumed for the weak decay of the B meson, then the semileptonic multiplicity is consistent with the recoil mass determined from the lepton momentum spectrum.
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No description provided.