G. Abbiendi et al., Test of the flavour independence of alpha(s) using next-to-leading order calculations for heavy quarks, EUR PHY J C, 11(4), 1999, pp. 643-659
We present a test of the flavour independence of the strong coupling consta
nt 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 obser
vables related to global event shapes were used to measure ct, in three fla
vour tagged samples (uds, c and b). The event shape distributions were fitt
ed by O(alpha(s)(2)) calculations of jet production taking into account mas
s effects for the c and b quarks. We find:
alpha(s)(c)/alpha(s)(uds) = 0.997 +/- 0.038 (stat.) +/- 0.030 (syst.) +/- 0
.012 (theory) and alpha(s)(b)/alpha(s)(uds) = 0.993 +/- 0.008 (stat.) +/- 0
.006 (syst.) +/- 0.011 (theory).