A higgs-like dilaton: viability and implications

Javi Serra

doi:10.1051/epjconf/20136017005

Abstract

We re-examine the feasibility of the higgs-like particle discovered at the LHC being a dilaton: the Goldstone boson of spontaneous breaking of scale invariance. We review the expected phenomenological deviations from the SM higgs and compare with other Goldstone higgs scenarios, with particular emphasis on double higgs production.

Highlights

The discovery of the long predicted higgs boson has brought unprecedented opportunities to unravel the nature of electroweak (EW) symmetry breaking
It is mandatory to re-evaluate our expectations for the physics giving rise to the EW scale, and already a great deal of repercussions have fallen upon, for instance, minimal supersymmetric models
Either the one arising from the spontaneous breaking of an internal global symmetry, which we refer to as the composite higgs, or the one from the spontaneous breaking of scale invariance (SBSI), the dilaton

Summary

Introduction

The discovery of the long predicted higgs boson has brought unprecedented opportunities to unravel the nature of electroweak (EW) symmetry breaking. As we learned from QCD, strong dynamics is able to naturally generate a large hierarchy between two distinct physical scales ΛIR ΛUV , while at the same time avoiding a large sensitivity of the former to the latter This is achieved by building a lagrangian with no relevant operators (unless protected by symmetry), but only operators close to marginality or irrelevant. It is further assumed that the lagrangian contains the proper dynamics for SBSI, in the form of the vacuum condensate of a scalar field, φ = f dφ , with ΛIR ∼ 4π f Such a breaking gives rise to one massless Goldstone boson, the dilaton, parametrized as χ ≡ f eσ(x)/ f (χ → eαχ under scaling). Our goal is to understand if the dilaton could really mimic the 125 GeV higgs, Sec. 2 and 3, and if so, what the differences with other higgs-like states would be, Sec 4

Dilaton mass

Μf log10 Μ GeV 12

Linear dilaton couplings

Double dilaton production