Using data collected from 1992 to 1995 with the ALEPH detector at LEP, a measurement of the colour factor ratios C-A/C-F and T-F/C-F and the strong coupling constant (alpha)(s) = (C-F x alpha(s) (M_Z))/(2 pi) 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. C-A/C-F = 2.20 +/- 0.09 (stat) +/- 0.13 (syst), T-F/C-F = 0.29 +/- 0.05 (stat) +/- 0.06 (syst). Fixing C-A/C-F and T-F/C-F to the QCD values permits a determination of alpha(s) (M_Z) and n(f), the number of active flavours. With this measurement the existence of a gluino with mass below 6.3 GeV/c(2) is excluded at 95% confidence level.

R., B., D., B., D., D., P., G., C., G., J. P., L., 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

CIOCCI, MARIA AGNESE;MARROCCHESI, PIER SIMONE;
1997-01-01

Abstract

Using data collected from 1992 to 1995 with the ALEPH detector at LEP, a measurement of the colour factor ratios C-A/C-F and T-F/C-F and the strong coupling constant (alpha)(s) = (C-F x alpha(s) (M_Z))/(2 pi) 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. C-A/C-F = 2.20 +/- 0.09 (stat) +/- 0.13 (syst), T-F/C-F = 0.29 +/- 0.05 (stat) +/- 0.06 (syst). Fixing C-A/C-F and T-F/C-F to the QCD values permits a determination of alpha(s) (M_Z) and n(f), the number of active flavours. With this measurement the existence of a gluino with mass below 6.3 GeV/c(2) is excluded at 95% confidence level.
1997
R., B., D., B., D., D., P., G., C., G., J. P., L., 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/11365/38139
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