Infrared and collinear safe event shape distributions and their mean values are determined using the data taken at five different centre of mass energies above M-Z with the DELPHI detector at LEP. From the event shapes, the strong coupling alpha(s) is extracted in O(alpha(s)(2)), NLLA and a combined scheme using hadronisation corrections evaluated with fragmentation model generators as well as using an analytical power ansatz. Comparing these measurements to those obtained at M-Z, the energy dependence (running) of alpha(s) is accessible. The logarithmic energy slope of the inverse strong coupling is measured to be d alpha(s)(-1)/d log(E-cm) = 1.39 +/- 0.34 (stat) +/- 0.17(syst), in good agreement with the QCD expectation of 1.27. (C) 1999 Published by Elsevier Science B.V. All rights reserved. RI De Angelis, Alessandro/B-5372-2009; Gonzalez Caballero, Isidro/E-7354-2010; Krammer, Manfred/A-6508-2010; Muresan, Raluca-Anca/C-3725-2011; Katsanevas, Stavros/A-4297-2011; Ruiz, Alberto/E-4473-2011; Marti-Garcia, Salvador/F-3085-2011; Verzi, Valerio/B-1149-2012; branchini, paolo/A-4857-2011; Shellard, Ronald/G-4825-2012; Petrolini, Alessandro/H-3782-2011; Fruhwirth, Rudolf/H-2529-2012; Monge, Maria Roberta/G-9127-2012

Energy dependence of event shapes and of alpha(s) at LEP 2

DE ANGELIS, Alessandro;DE LOTTO, Barbara;SCURI, Fabrizio;
1999-01-01

Abstract

Infrared and collinear safe event shape distributions and their mean values are determined using the data taken at five different centre of mass energies above M-Z with the DELPHI detector at LEP. From the event shapes, the strong coupling alpha(s) is extracted in O(alpha(s)(2)), NLLA and a combined scheme using hadronisation corrections evaluated with fragmentation model generators as well as using an analytical power ansatz. Comparing these measurements to those obtained at M-Z, the energy dependence (running) of alpha(s) is accessible. The logarithmic energy slope of the inverse strong coupling is measured to be d alpha(s)(-1)/d log(E-cm) = 1.39 +/- 0.34 (stat) +/- 0.17(syst), in good agreement with the QCD expectation of 1.27. (C) 1999 Published by Elsevier Science B.V. All rights reserved. RI De Angelis, Alessandro/B-5372-2009; Gonzalez Caballero, Isidro/E-7354-2010; Krammer, Manfred/A-6508-2010; Muresan, Raluca-Anca/C-3725-2011; Katsanevas, Stavros/A-4297-2011; Ruiz, Alberto/E-4473-2011; Marti-Garcia, Salvador/F-3085-2011; Verzi, Valerio/B-1149-2012; branchini, paolo/A-4857-2011; Shellard, Ronald/G-4825-2012; Petrolini, Alessandro/H-3782-2011; Fruhwirth, Rudolf/H-2529-2012; Monge, Maria Roberta/G-9127-2012
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11390/883655
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