Next-to-Leading Order Calculation of Four-Jet Shape Variables

Abstract

We present the next-to-leading order calculation of two four-jet event shape variables, the D parameter and acoplanarity differential distributions. We find large, more than 100% radiative corrections. The theoretical prediction for the D parameter is compared to L3 data obtained at the Z peak and corrected to hadron level.

Figures (3)

• Figure 1: Renormalization scale dependence of the average value of the D parameter. $x_\mu = \mu/\sqrt{s}$
• Figure 2: K factor of the D parameter and acoplanarity.
• Figure 3: Comparison of the next-to-leading order QCD prediction for the D parameter differential distribution, $\frac{{\rm D}}{\sigma}\frac{{\rm d}\sigma}{{\rm d} {\rm D}}$ to L3 data obtained at the $Z^0$ peak and corrected to hadron level. The upper edge of the theoretical band is obtained with renormalization scale $x_\mu=0.1$, while the lower edge at $x_\mu = 1$.