Resummation of soft and hard gluon radiation in perturbative QCD

This thesis arises in the context of precision measurements at hadron colliders. The Tevatron and the LHC provide very accurate measurements of many Standard Model processes, such as the production of a lepton pair (Drell-Yan) of high invariant mass. An accurate theoretical prediction of such processes is crucial to be able to distinguish Standard Model physics from possible new physics signals. QCD effects in the computation of the cross-sections at hadron colliders are usually sizable; in particular, in some kinematical regimes they behave in a non-perturbative way. In these cases the resummation of the whole perturbative series is needed for accurate phenomenological predictions. In this thesis the impact of threshold and high-energy resummations for the production of high invariant mass systems (Drell-Yan, Higgs) are studied in detail. In particular, in the threshold case a prescription to deal with the divergent nature of the perturbative series based on Borel summation is presented, and compared with the other prescriptions in the literature. Results for the invariant mass distributions and rapidity distributions are presented. The high-energy resummation formalism is reviewed and improved, and its impact in phenomenological applications at hadron colliders is investigated. In particular, a possible interaction between the two resummation regimes is studied in some detail.