Brambilla, NoraGarcia i Tormo, XavierSoto Riera, JoanVairo, Antonio2019-04-042019-04-042007-04-181550-7998https://hdl.handle.net/2445/131418We improve on a recent determination of α s from Γ ( Υ ( 1 S ) → γ X ) / Γ ( Υ ( 1 S ) → X ) with CLEO data by taking into account color octet contributions and avoiding any model dependence in the extraction. We obtain α s ( M Υ ( 1 S ) ) = 0.184 + 0.015 − 0.014 , which corresponds to α s ( M Z ) = 0.119 + 0.006 − 0.005 .5 p.application/pdfeng(c) American Physical Society, 2007Física de partículesQuarksParticle physicsQuarksinfo:eu-repo/semantics/article5511302019-04-04info:eu-repo/semantics/openAccess