Bestimmung der starken Kopplungskonstanten #alpha#_s(M_Z"2) unter Beruecksichtigung vollstaendiger resummierter fuehrender und naechstfuehrender Logarithmen Analyse von globalen Ereignisvariablen gemessen in hadronischen Z-Zerfaellen

The value of the strong coupling constant #alpha#_s is determined from a combined analysis of the global event shape variables thrust, heavy jet mass and total and wide jet broadening. The extraction of #alpha#_s includes the full calculation of O(#alpha#_s"2) terms and leading and next-to-leading logarithms resummed to all orders of #alpha#_s. The analysis is based on data taken with the DELPHI detector at LEP during 1991 and 1992. The dependence of the result on the detailed matching of the resummed and fixed order terms is studied. The result from the combined theory is compared with values coming from a pure NLLA analysis and as pure O(#alpha#_s"2) analysis, respectively. It is found that the inclusion of the resummed logarithms allows the description of the data in the two jet range and reduces the scale dependence of #alpha#_s(M_Z"2) compared to pure O(#alpha#_s"2) theory. The value using the combined NLLA+O(#alpha#_s"2) theory at the scale #mu#"2=M_Z"2 is #alpha#_S(M_Z"2)=0.118#+-#0.007. The running of #alpha#_s is measured from the 1991 data in an energy range from 88.5 to 93.7 GeV. The slope of #alpha#_s obtained at the Z peak is d#alpha#_s/dQ/_Q_=_M_z=-(2.9#+-#2.8)x10"-"4GeV"-"1. This value is compatible with QCD and exludes an abelian gluon model with more than two standard deviations. (orig.)SIGLEAvailable from TIB Hannover: RO 9740(94-2) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman