New jet cluster algorithms: next-to-leading order QCD and hadronization corrections

Abstract

New algorithms have been proposed as alternatives to the standard JADE-type algorithms for quantifying jet production in e+e− annihilation. We study in detail the “Durham” algorithm, based on clustering according to relative transverse momentum, and introduce a new “Geneva” variation which is expected to exhibit similar theoretical properties of exponentiation at small jet resolution. In particular, we calculate the next-to-leading order perturbative corrections to the three-jet rate for the new algorithms, and we study non-perturbative corrections using the JETSET parton-shower Monte Carlo. In each case we compare to the results obtained with the usual JADE-type algorithms. We conclude that the new algorithms exhibit somewhat smaller perturbative corrections compared to the standard algorithms, and that the non-perturbative corrections are of comparable size. Thus the new algorithms appear to be at least as well suited to precision measurements of the strong coupling.