Predictions to all orders in perturbative quantum chromodynamics for high energy collider experiments

Abstract

This thesis discusses an implementation of automated all orders calculations in perturbative quantum chromodynamics and its application to measurements at recent collider experiments. It is realised as a plugin to the SHERPA event generator framework. The theoretical basis is provided by the well established CAESAR formalism. This allows one to take into account the leading and next-to-leading logarithmic enhanced terms. NLO+NLL 0 accuracy is achieved by matching the resulting expressions to calculations at next-to-leading order in the strong coupling constant. Non-perturbative corrections are transferred from Monte Carlo simulations to the all orders distributions. Going beyond the original CAESAR formalism, soft drop groomed observables as well as jet substructure variables are discussed in the same framework. Use cases are illustrated with various examples. In electron positron annihilation, the resummation of high multiplicity jet rates is presented, as well as an analysis of the potential of soft drop grooming, applied to the thrust observable, to improve fits of the strong coupling constant. Relevant to the currently operating Large Hadron Collider are the phenomenological studies of soft drop groomed global event shapes in proton proton collisions and predictions for jet substructure observables. The latter are compared to recent measurements by the CMS experiment. i AuthorshipThe original research presented in this thesis has been worked on and published in collaboration with the respective co-authors in the peer-reviewed publications [I] Fitting the Strong Coupling Constant with Soft-Drop Thrust