344284 SzGeCERN 20161219131714.0 oai:cds.cern.ch:344284 cerncds:FULLTEXT cerncds:CERN:FULLTEXT cerncds:CERN CERN-OPEN-98-001 eng WU-B-97-38 Hahn, S Wuppertal U. New Results on $\alpha_{s}$ from DELPHI 1999 Wuppertal Wuppertal TU. Fachbereich Phys. 1 Dec 1997 5 p paper Recent studies of the strong coupling \as using the DELPHI detector at LEP \cite{pap1,pap2} are reviewed. For the analysis of the data at $ \sqrt{s} = M_Z $ recorded in 1994, a large number of shape observables and their dependence on the event orientation are measured and compared to theoretical calculations in $ { \cal O } ( \alpha_s^2 ) $ . The adjustment of the renormalization scale $ \mu $ turns out to be of major importance. Only a poor description of the data can be achieved if the so-called physical scale $ \mu^2 = Q^2 $ is applied, whereas a combined fit of $ \alpha_s $ and the renormalization scale value yields an excellent description of the high statistics data. For these scale values perfect consistency of the fit values of $ \alpha_s(M_Z) $ is obtained for all event shape observables considered. The running of $ \alpha_s $ is measured from the DELPHI data at $ \sqrt{s} $ = 130 GeV - 172 GeV. Here an analytical power ansatz for the hadronization corrections is compared with hadronization corrections obtained by using Monte Carlo generators. SzGeCERN Particle Physics - Experiment ARTICLE CERN CERN LEP DELPHI PPE CERN Depot 4, bldg. 500-S-023 (DE4) CERN-OPEN-98-001 http://preprints.cern.ch/cgi-bin/setlink?base=preprint&categ=cern&id=OPEN-98-001 Access to fulltext document http://cds.cern.ch/record/344284/files/open-98-001.pdf Access to fulltext document http://cds.cern.ch/record/344284/files/open-98-001.ps.gz Access to fulltext document n 199805 a2000 13 20101108 1207 CER01 19980129 319858 509-512 jerusalem970819 PUBLIC 000268238CER ARTICLE ConferencePaper