NLO QCD and electroweak corrections to W[gamma] and Z[gamma] production

Hochschulschrift

Zusammenfassung: In this thesis we investigate the production of a massive weak vector boson W ± or Z in association with a photon, where the vector boson decays leptonically. This type of processes is particularly interesting, since it allows to test the non-Abelian couplings of the EW gauge bosons. Furthermore, the channel pp → Zγ → l + l − γ is the main background to the Higgs-decay channel pp → h → Zγ, and Vγ (V = W, Z) production is an important background for various new-physics searches. In this thesis we present the calculation of the full NLO QCD+EW corrections. Therefore, we first reproduce the well known NLO QCD corrections. The EW corrections are calculated including the decay of the massive vector boson and taking into account all off-shell effects. The finite widths of the W and the Z boson are implemented by using the complex-mass scheme. Contributions from photon-induced channels are also taken into account applying up-to-date photon PDFs. Considering the fact that electrons and muons have different signatures in the detectors we present results for dressed leptons and bare muons. Calculating NLO corrections infra red divergences appear during the numerical integration of the real corrections. These divergences cancel against their counterparts in the virtual corrections as dictated by the KLN theorem. In order to extract the infra red divergences from the real corrections, we apply a so-called dipole subtraction algorithm allowing for a proper numerical integration of the real corrections. Separating hard photons from collinear jets, a quark-to-photon fragmentation function in combination with so-called democratic clustering ́a la Glover and Morgan is employed. As an alternative we also apply Frixione’s isolation scheme. Finally, anomalous ZγV (V = W, Z) and WWγ couplings are implemented at the level of NLO QCD. We present integrated cross sections for the LHC at 7 TeV, 8 TeV, and 14 TeV. Furthermore, we show differential distributions at 14 TeV with and without anomalous couplings and discuss the different types of relative corrections. The impact of EW corrections on differential distributions can reach several 10% in certain distributions due to so-called Sudakov logarithms, while their impact on integrated cross sections is of the order of a few percent. In contrast, the QCD corrections are huge in integrated cross sections as well as in differential distributions

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch
• Anmerkungen: Albert-Ludwigs-Universität Freiburg, Dissertation, 2015

Klassifikation und Themen

• Klassifikation: Physik
• Schlagwort: Elementarteilchenphysik ; Elektroschwache Wechselwirkung ; Hochenergiephysik ; Quantenchromodynamik ; Theoretische Physik

Beteiligte, Orts- und Zeitangaben

• Ereignis: Veröffentlichung
• (wo): Freiburg
• (wer): Universität
• (wann): 2016
• Urheber: Hecht, Markus
• Beteiligte Personen und Organisationen: Dittmaier, Stefan

Weitere Informationen

• DOI: 10.6094/UNIFR/10629
• URN: urn:nbn:de:bsz:25-freidok-106294
• Rechteinformation: Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 14.08.2025, 10:52 MESZ