A Measurement of the b quark mass from hadronic Z decays

Hadronic Z decay data taken with the ALEPH detector at LEP1 are used to measure the three-jet rate as well as moments of various event-shape variables. The ratios of the observables obtained from b-tagged events and from an inclusive sample are determined. The mass of the b quark is extracted from a fit to the measured ratios using a next-to-leading order prediction including mass effects. Taking the first moment of the y3 distribution, which is the observable with the smallest hadronization corrections and systematic uncertainties, the result is: mb(MZ) = [3.27+-0.22(stat) +-0.22(exp)+-0.38(had)+-0.16(theo)] GeV/c2. The measured ratio is alternatively employed to test the flavour independence of the strong coupling constant for b and light quarks.

Note:

20 pages, 7 figures, submitted to ICHEP2000, Osaka Report-no: CERN-EP/2000-093

talk: Osaka 2000/07/27
electron positron: colliding beams
electron positron: annihilation
Z0: electroproduction
Z0: hadronic decay
bottom: pair production
mass: bottom
event shape analysis
particle identification: bottom
quantum chromodynamics: perturbation theory

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