QCD studies with ${\rm e^+e^-}$ annihilation data at 172-189 GeV

• DOI: 10.1007/s100520050015
• Publication Date: 2002-08-25T01:57:49Z
• Authors: G. Abbiendi et al.
• Keywords: Annihilation; Multiplicity (mathematics); Electron–positron annihilation

We have studied hadronic events from e+e- annihilation data at centre-of-mass energies of sqrt{s}=172, 183 and 189 GeV. The total integrated luminosity of the three samples, measured with the OPAL detector, corresponds to 250 pb^-1. We present distributions of event shape variables, charged particle multiplicity and momentum, measured separately in the three data samples. From these we extract measurements of the strong coupling alpha_s, the mean charged particle multiplicity and the peak position xi_0 in the xi_p=ln(1/x_p) distribution. In general the data are described well by analytic QCD calculations and Monte Carlo models. Our measured values of alpha_s, and xi_0 are consistent with previous determinations at sqrt{s}=MZ.<br/>49 pages, 13 figures, submitted to Eur. Phys. J. C<br/>