2019 Impact factor 4.389
Particles and Fields
Eur. Phys. J. C 11, 643-659
DOI 10.1007/s100529900225

Test of the flavour independence of $\alpha_s$ using next-to-leading order calculations for heavy quarks

The OPAL Collaboration

G.Abbiendi$^{\rm 2}$ - et al.

2 Dipartimento di Fisica dell' Università di Bologna and INFN, 40126 Bologna, Italy

Received: 18 March 1999 / Published online: 14 October 1999

We present a test of the flavour independence of the strong coupling constant for charm and bottom quarks with respect to light (uds) quarks, based on a hadronic event sample obtained with the OPAL detector at LEP. Five observables related to global event shapes were used to measure \ensuremath{\alpha_s} in three flavour tagged samples (uds, c and b). The event shape distributions were fitted by \ensuremath{\mathcal{O}(\alpha_s^2)} calculations of jet production taking into account mass effects for the c and b quarks. We find:
${\alpha_s^\mathrm{c}/\alpha_s^\mathrm{uds}}= 0.997
\pm 0.038 (stat.) \pm 0.030 (syst.) \pm 0.012 (theory)\quad$ and ${\alpha_s^\mathrm{b}/\alpha_s^\mathrm{uds}}= 0.993
\pm 0.008 (stat.) \pm 0.006 (syst.) \pm 0.011 (theory)$.

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