Soft-Collinear Effects in Threshold and Joint Resummation

Abstract

Large perturbative corrections, which appear in perturbative expressions for many QCD observables, either at small QT or at partonic threshold, can be organized by way of all order resummation. Joint resummation allows simultaneous resummation of threshold and recoil effects and its impact has been assessed upto leading log, next-to-leading log (NLL) and in some cases up to NNLL accuracy. We discuss another class of terms, called soft-collinear effects, which give rise to corrections of the form lnjNN and their impact on the joint resummed calculations of prompt photon production cross section.