Subtraktionsschemata in nächst-zu-nächst-zu-führender Ordnung mit Anwendungen in Top-Quark und Jet Physik
Zusammenfassung der Projektergebnisse
The general goal of this project was to push the frontier of perturbative Quantum Chromodynamics in application to collider processes, in particular for the Large Hadron Collider. We have made major advances in top-quark physics and worked on special tools for the automation of calculations at next-to-next-to-leading order in QCD. One of our main achievements is a set of predictions for differential distributions in top-quark pair production at the LHC. These results have been eagerly awaited by the experimental collaborations, and are now routinely used to compare to measurement data. Furthermore, we have been able to show that some persistent discrepancies between theory and experiment in the transverse momentum distribution of the top-quark can be explained by inclusion of higher-order perturbative effects. We have performed thorough studies of convergence of perturbation theory and estimated the current precision of differential predictions at the few percent level. This allowed us to provide prescriptions for efficient resonance searches in invariant mass distributions. As an important contribution to hadron collider physics, we have demonstrated that top-quark pair production can be used to constrain the high-x gluon distribution function in the proton. We have also provided the necessary tools for PDF fitting collaborations to include top-quark data in their fits. Finally, we have studied the effect of electroweak corrections and demonstrated that their inclusion is only necessary in the top-quark transverse momentum distribution at high energy. Other distributions, which are routinely used for searches and fits can be safely taken with QCD corrections only. This information is very valuable to various communities in particle physics. The research started in this project will be the basis of further studies in many directions. In particular, the problem of inclusion of top-quark decays with NNLO precision in QCD, while urgent from the point of view of phenomenology, is still unsolved. The applications to top-quark physics listed above were only made possible by general computer tools for perturbative QCD. The further development of these tools will be one of our main priorities in the years to come.
Projektbezogene Publikationen (Auswahl)
- “Bump hunting in LHC tt¯ events”, Phys. Rev. D 94 (2016) no.11, 114033
M. Czakon, D. Heymes and A. Mitov
- “High-precision differential predictions for top-quark pairs at the LHC”, Phys. Rev. Lett. 116 (2016) no.8, 082003
M. Czakon, D. Heymes and A. Mitov
- “NNLO QCD predictions for fully-differential top-quark pair production at the Tevatron”, JHEP 1605 (2016) 034
M. Czakon, P. Fiedler, D. Heymes and A. Mitov
- “Dynamical scales for multi-TeV top-pair production at the LHC”, JHEP 1704 (2017) 071
M. Czakon, D. Heymes and A. Mitov
