Analysis of exclusive k(T) jet algorithms in electron-positron annihilation

Abstract

We study the factorization of the dijet cross section in e(+)e(-) annihilation using the generalized exclusive jet algorithm which includes the cone-type, the JADE, the k(T), the anti-k(T) and the Cambridge/Aachen jet algorithms as special cases. In order to probe the characteristics of the jet algorithms in a unified way, we consider the generalized k(T) jet algorithm with an arbitrary weight of the energies, in which various types of the k(T)-type algorithms are included for specific values of the parameter. We show that the jet algorithm respects the factorization property for the parameter alpha < 2. The factorized jet function and the soft function are well defined and infrared safe for all the jet algorithms except the k(T) algorithm. The k(T) algorithm (alpha = 2) breaks the factorization since the jet and the soft functions are infrared divergent and are not defined for alpha = 2, though the dijet cross section is infrared finite. In the jet algorithms which enable factorization, we give a phenomenological analysis using the resummed and the fixed-order results.