Simple Quantum-Chromodynamics Prediction of Jet Structure ine+e−Annihilation

Abstract

We propose a simple alternative to the sphericity as a measure of jet structure in $e^{+}{e}^{-}$ annihilation. Our variable has the property that it can be reliably calculated in perturbation theory in quantum chromodynamics (QCD) for large $Q^2$. It is not sensitive to the details of quark and gluon decay into color-singlet hadrons. We discuss the nonperturbative effects which are important at moderate $Q^2$.