Test of the flavour independence of αs

UNSPECIFIED (1995) Test of the flavour independence of αs. Physics Letters B, 355 (1-2). pp. 381-393. ISSN 0370-2693

Abstract

Using about 950000 hadronic events collected during 1991 and 1992 with the ALEPH detector, the ratios and have been measured in order to test the flavour independence of the strong coupling constant αs. The analysis is based on event-shape variables using the full hadronic sample, two b-quark samples enriched by lepton tagging and lifetime tagging, and a light-quark sample enriched by lifetime antitagging. The combined results are rb = 1.002±0.023 and ruds = 0.971 ± 0.023.