Bestimmung der b-Quarkmasse an der Z-Massenskala

In hadronic decays of the Z boson recorded in 1994 with the OPAL detector at LEP b quark events were selected using the long lifetime of b flavoured hadrons. Different observables for the determination of the b quark mass were studied. Jetrates were found to be best suited. The 3-jet rates in b quark events for seven different jetfinder were compared to the 3-jet rate in light quark events, and a clear deviation from unity was found. A combination of all seven individual jet finders yielded for the $MS$ mass mb(mz) = ( 2.67 pm 0.03 (stat.) +0.29 -0.37 (syst.) pm 0.19 (theo.) GeV The running of the b quark mass as predicted by QCD is confirmed and together with the value estimated at the scale of the production threshold of mb(PDG,mb)=(4.2 pm 0.2) GeV , a constant mass in the MSbar scheme is ruled out by 3.9 standard deviations. The main contributions to the total uncertainty come from the modelling of the b quark fragmentation and the simulation related to the b selection and the simulation of the detector in general.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2001

Author dc:creator

• Seuster, Rolf

Contributors dc:contributor

• Bethke, Siegfried

• info:eu-repo/classification/ddc/530
• Physik
• b-Quark
• Masse
• Z-Boson
• Hadronischer Zerfall
• Schweres Quark
• Massenbestimmung

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-122199%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:60492