Four-jet angular distributions and color charge measurements: leading order versus next-to-leading order

Abstract

We present the next-to-leading order perturbative QCD prediction to the four-jet angular distributions used by experimental collaborations at LEP for measuring the QCD color charge factors. We compare our results to ALEPH data corrected to parton level. We perform a leading order ``measurement'' of the QCD color factor ratios by fitting the leading order perturbative predictions to the next-to-leading order result. Our result shows that in an experimental analysis for measuring the color charge factors the use of the O(${\alpha }_s^3$) QCD predictions instead of the O(${\alpha }_s^2$) results may shift the center of the fit by a relative factor of $1+2\text{as}$ in the $T_R/C_F$ direction.

Comments: 14 pages, 10 tables, 5 figures, revtex, eps styles