Eur. Phys. J. C (2009) 64: 25-33
https://doi.org/10.1140/epjc/s10052-009-1129-5

Regular Article - Experimental Physics

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

The University of Manchester, Oxford Road, Manchester, M13 9PL, UK

^* e-mail: paul.bell@cern.ch

Received: 5 August 2009
Revised: 17 August 2009
Published online: 18 September 2009

Abstract

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.