A measurement of the QCD colour factors and a limit on the light gluino

Using data collected from 1992 to 1995 with the ALEPH detector at LEP, a measurement of the colour factor ratios CA/CF and TF /CF and the strong coupling constant αs = CFαs(MZ)/(2π) has been performed by fitting theoretical predictions simultaneously to the measured differential two-jet rate and ang...

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Bibliographic Details
Main Authors: BARATE, R.; et al., THULASIDAS, M.
Format: text
Language:English
Published: Institutional Knowledge at Singapore Management University 1997
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Online Access:https://ink.library.smu.edu.sg/sis_research/5757
https://ink.library.smu.edu.sg/context/sis_research/article/6760/viewcontent/ppe_97_002.pdf
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Institution: Singapore Management University
Language: English
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Summary:Using data collected from 1992 to 1995 with the ALEPH detector at LEP, a measurement of the colour factor ratios CA/CF and TF /CF and the strong coupling constant αs = CFαs(MZ)/(2π) has been performed by fitting theoretical predictions simultaneously to the measured differential two-jet rate and angular distributions in four-jet events. The result is found to be in excellent agreement with QCD, {fx4-1} Fixing CA/CF and TF/CF to the QCD values permits a determination of αs(MZ) and ηf, the number of active flavours. With this measurement the existence of a gluino with mass below 6.3 GeV/c2 is excluded at 95% confidence level.