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 ᾱs = 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, CA/CF = 2.20 ± 0.09 (stat) ± 0.13 (syst), TF/CF = 0.29 ± 0.05 (stat) ± 0.06 (syst). Fixing CA/CF and TF/CF to the QCD values permits a determination of αs(MZ) and nf, 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.

Barate, R., Buskulic, D., Decamp, D., Ghez, P., Goy, C., Lees, J., et al. (1997). A measurement of the QCD colour factors and a limit on the light gluino. ZEITSCHRIFT FÜR PHYSIK. C, PARTICLES AND FIELDS, 76(1), 1-14 [10.1007/s002880050522].

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

CARPINELLI, Massimo;
1997

Abstract

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 ᾱs = 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, CA/CF = 2.20 ± 0.09 (stat) ± 0.13 (syst), TF/CF = 0.29 ± 0.05 (stat) ± 0.06 (syst). Fixing CA/CF and TF/CF to the QCD values permits a determination of αs(MZ) and nf, 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.
Articolo in rivista - Articolo scientifico
Physics
English
1997
76
1
1
14
none
Barate, R., Buskulic, D., Decamp, D., Ghez, P., Goy, C., Lees, J., et al. (1997). A measurement of the QCD colour factors and a limit on the light gluino. ZEITSCHRIFT FÜR PHYSIK. C, PARTICLES AND FIELDS, 76(1), 1-14 [10.1007/s002880050522].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/390206
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