Next-to-leading power threshold effects for inclusive and exclusive processes with final state jets

It is well known that cross-sections in perturbative QCDreceive large corrections from soft and collinearradiation, whose properties must be resummed to all orders in the coupling. Whether or not the universal propertiesof this radiation can be extended to next-to-leading power (NLP) in the threshold expansion has been the subject of much recent study. In this paper, we consider two types of NLP effects: the interplay of next-to-soft and collinearradiation in processes with final state jets and the NLP contributions stemming from soft quarks. We derive an NLP amplitude for soft gluons and quarks, valid for an arbitrary number of coloured or colourless massless final state particles. We show explicitly that this framework can be used to correctly obtain the dominant NLP effects in three different types of processes at next-to-leading order: deep-inelastic scattering, hadroproduction via electron-positron annihilationand prompt photon production. Our results provide an important ingredient for developing a universal resummationformalism for NLP effects.