Effective field theory approach to the Higgs lineshape

Abstract

The phenomenology of unstable particles, including searches and exclusion limits at the LHC, depends significantly on its lineshape. When the width of the resonance is large with respect to its mass, off-shell effects become relevant and the very same definition of width becomes non trivial. Taking a heavy Higgs boson as an example, we propose a new formulation to describe the lineshape via an effective field theory approach. Our method leads to amplitudes that are gauge invariant, respect unitarity and can appropriately describe the lineshape of broad resonances. The application of the method to the following relevant processes for the LHC phenomenology have been considered: gluon fusion, vector boson scattering and $t\bar{t}$ production via weak boson fusion.

15 pages, 16 figures

References in corpus (6)

• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
• The Lee-Wick Standard Model
• The complex-mass scheme for perturbative calculations with unstable particles
• Combined search for the Standard Model Higgs boson in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
• Higgs Pseudo-Observables, Second Riemann Sheet and All That
• Two-Loop Threshold Singularities, Unstable Particles and Complex Masses