Quartic gauge couplings and the radiation zero in pp→l±νγγ events at the LHC

• Published in: The European physical journal. C, Particles and fields Particles and fields, 2009-11, Vol.64 (1), p.25-33, Article 25
• Main Author: Bell, P. J.
• Format: Article
• Language: English
• Subjects: Astronomy; Astrophysics and Cosmology; Computer simulation; Couplings; Elementary Particles; Hadrons; Heavy Ions; Large Hadron Collider; Leptons; Luminosity; Measurement Science and Instrumentation; Nuclear Energy; Nuclear Physics; Photons; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Regular Article - Experimental Physics; String Theory
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-009-1129-5

We report a study of the process pp→l ± νγγ at CERN’s Large Hadron Collider, using a leading order partonic-level event generator interfaced to the Pythia program for showering and hadronisation and a with a generic detector simulation. The process is sensitive to possible anomalous quartic gauge boson couplings of the form WWγγ. It is shown how unitarity-safe limits may be placed on these anomalous couplings by applying a binned maximum likelihood fit to the distribution of the two-photon invariant mass, M γγ , below a cutoff of ∼1 TeV. Assuming 30 fb −1 of integrated luminosity, the expected limits are two orders of magnitude tighter than those available from LEP. It is also demonstrated how the Standard Model radiation zero feature of the q process may be observed in the difference between the two-photon and charged lepton pseudo-rapidities.