Kallweit, Stefan (2008): Precision Calculations for GaugeBoson Pair Production with a Hadronic Jet at Hadron Colliders. Dissertation, LMU München: Faculty of Physics 

PDF
Kallweit_Stefan.pdf 4MB 
Abstract
Gaugeboson pairproduction processes with an additional hadronic jet are of particular interest as background to Higgs and newphysics searches at hadron colliders. Moreover, they enablebesides genuine gaugeboson pair productiona direct analysis of the nonAbelian gaugeboson selfinteractions in the electroweak sector. In this work we provide precision calculations for the processes pp>VV+jet+X. In detail, corrections to WW+jet, ZZ+jet, and WZ+jet production are evaluated at nexttoleadingorder in the strong coupling (NLO QCD). Particular care has to be taken when treating the infrared singularities arising in the virtual and real corrections. The FormCalc/LoopTools package is applied for the virtual corrections, where dimensionally regularized infrareddivergent integrals are added to the FF library which is used for the regular ones. The realemission matrix elements are evaluated in terms of helicity amplitudes in the WeylvanderWaerden formalism. The CataniSeymour dipole subtraction formalism mediates the cancellation of infrared divergences between the two contributions. To perform the numerical integration a multichannel Monte Carlo integrator is written in C++, which is designed to meet the requirements of integrating cross sections in the dipole subtraction formalism. For all gaugeboson assignments, the NLO QCD corrections significantly stabilize the artificial dependence of the leadingorder (LO) cross sections on renormalization and factorization scales for Tevatron. For LHC, however, only a modest reduction of the scale dependence results unless a veto on a second hard jet is applied. Beyond investigating the production processes, leptonic decays of the gauge bosons are considered. To this end, a full amplitude calculation including resonant and nonresonant contributions to the leptonic final states, a simple narrowwidth approximation (NWA), and an improved version of the NWA that takes into account spin correlations are performed at LO. Comparing these approaches the improved NWA turns out to deliver an appropriate approximation to the decays at a reasonable level of accuracy. Thus, an NLO QCD calculation to VV+jet including leptonic decays is performed in the framework of the improved NWA. Several results on differential cross sections for quantities of the jet and the decay leptons are presented. For WW+jet, we discuss both protonproton collisions at LHC and protonantiproton collisions at Tevatron. For WZ+jet and ZZ+jet, however, the cross sections at Tevatron are too small, so only results for LHC are presented. The Monte Carlo generator developed in this thesis can be used as a tool in data analysis at LHC and Tevatron.
Item Type:  Thesis (Dissertation, LMU Munich) 

Subjects:  500 Natural sciences and mathematics 500 Natural sciences and mathematics > 530 Physics 
Faculties:  Faculty of Physics 
Language:  English 
Date of oral examination:  21. November 2008 
1. Referee:  Dittmaier, Stefan 
MD5 Checksum of the PDFfile:  17ac16307ae8f8c7a19d009c0dfe458b 
Signature of the printed copy:  0001/UMC 17423 
ID Code:  9362 
Deposited On:  04. Dec 2008 09:17 
Last Modified:  19. Jul 2016 16:26 