Heavy jet mass distribution in e +e − annihilation

Abstract

Predictions are presented for the distribution of ϱ= M h 2/ s in e +e − annihilation, where s is the centre-of-mass energy squared and M h is the heavy jet mass, defined as the greater if the invariant masses of two hemispheres separated by the plane normal to the thrust axis. The calculation includes resummation of leading and next-to-leading logarithms of ϱ to all orders in QCD perturbation theory, together with non-logarithmic terms up to second order. This reduces the renormalization scale dependence relative to the fixed-order calculation and should permit the strong coupling constant to be measured accurately using a larger region of the distribution.