Measurement of the Charged Multiplicity of Z0→bb¯ Events
PhysRevLett_72_3145.pdf 868 KB
Using an impact parameter tag to select an enriched sample of Z0→bb¯ events, we have measured the difference between the average charged multiplicity of Z0→bb¯ and Z0→ hadrons to be n¯b-n¯had=2.24±0.30 ( stat )±0.33 ( syst ) tracks per event. From this, we have derived n¯b-n¯uds=3.31±0.41±0.79. Comparing this measurement with those at lower center-of-mass energies, we find no evidence that n¯b-n¯uds depends on energy. This result is in agreement with a precise prediction of perturbative QCD, and supports the notion that QCD remains asymptotically free down to the scale Mb2.
Physical Review Letters
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American Physical Society
Copyright (c) 1994 American Physical Society.
Graduate School of Advanced Sciences of Matter