Using 109 000 hadronic events obtained with the ALEPH detector at LEP at energies close to the Z resonance peak, the strong coupling constant alpha(s) (M(Z)2) is determined from an analysis of the global event shape variables thrust, heavy jet mass and the differential two-jet rate based on the k(T)-clustering scheme. The analysis uses improved theoretical predictions in which leading and next-to-leading logarithms, resummed to all orders, supplement second order expressions. After combining the results from all variables, alpha(s) (M(Z)2) is measured to be 0. 12 5 +/- 0.005, where the error is the quadratic sum of experimental and theoretical uncertainties, and is dominated by the latter.
MEASUREMENT OF ALPHA-S IN HADRONIC Z-DECAYS USING ALL-ORDERS RESUMMED PREDICTIONS
LUSIANI, Alberto;ROLANDI, LUIGI;LIGABUE, FRANCO;
1992
Abstract
Using 109 000 hadronic events obtained with the ALEPH detector at LEP at energies close to the Z resonance peak, the strong coupling constant alpha(s) (M(Z)2) is determined from an analysis of the global event shape variables thrust, heavy jet mass and the differential two-jet rate based on the k(T)-clustering scheme. The analysis uses improved theoretical predictions in which leading and next-to-leading logarithms, resummed to all orders, supplement second order expressions. After combining the results from all variables, alpha(s) (M(Z)2) is measured to be 0. 12 5 +/- 0.005, where the error is the quadratic sum of experimental and theoretical uncertainties, and is dominated by the latter.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
