2018 Impact factor 4.843
Particles and Fields
Eur. Phys. J. C 18, 1-13
DOI 10.1007/s100520000533

A measurement of the b-quark mass from hadronic Z decays

The ALEPH Collaboration

R. Barate - et al.

Laboratoire de Physique des Particules (LAPP), IN2P3-CNRS, 74019 Annecy-le-Vieux Cedex, France

Received: 6 July 2000 / Published online: 13 November 2000 - © Springer-Verlag 2000

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

\begin{displaymath}m_b(M_{\mathrm Z}) = \left[3.27 \,\pm\,0.22 (\mathrm{stat})
\;{\ifmmode \mathrm{GeV}/c^2\else GeV/$c^2$\fi}\quad.\end{displaymath}

The measured ratio is alternatively employed to test the flavour independence of the strong coupling constant for b and light quarks.

Copyright Società Italiana di Fisica, Springer-Verlag 2000