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 y(3) distribution, which is the observable with the smallest hadronization corrections and systematic uncertainties, the result is m(b)(M(z)) = [3.27 +/- 0.22(stat) +/- 0.22(exp) +/- 0.38(had) +/- 0.16(theo)] GeV/c(2) . The measured ratio is alternatively employed to test the flavour independence of the strong coupling constant for b and light quarks.
A measurement of the b-quark mass from hadronic Z decays
SELVAGGI, Giovanna;NUZZO, Salvatore Vitale;DE PALMA, Mauro
2000-01-01
Abstract
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 y(3) distribution, which is the observable with the smallest hadronization corrections and systematic uncertainties, the result is m(b)(M(z)) = [3.27 +/- 0.22(stat) +/- 0.22(exp) +/- 0.38(had) +/- 0.16(theo)] GeV/c(2) . The measured ratio is alternatively employed to test the flavour independence of the strong coupling constant for b and light quarks.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
