A Higgslike Dilaton

TL;DR

This paper explores the hypothesis that the 125 GeV Higgs-like resonance could be a dilaton, analyzing its couplings, mass tuning issues, and implications within scale-invariant theories.

Contribution

It demonstrates that a dilaton can mimic Higgs couplings if the scale f is close to the electroweak scale and discusses the challenges in keeping the dilaton light without fine-tuning.

Findings

Dilaton can reproduce observed Higgs couplings for f ~ v

Light dilaton mass requires tuning or specific dynamical assumptions

Dilaton mass naturally comparable to the dynamical scale Lambda

Abstract

We examine the possibility that the recently discovered 125 GeV higgs like resonance actually corresponds to a dilaton: the Goldstone boson of scale invariance spontaneously broken at a scale f. Comparing to LHC data we find that a dilaton can reproduce the observed couplings of the new resonance as long as f ~ v, the weak scale. This corresponds to the dynamical assumption that only operators charged under the electroweak gauge group obtain VEVs. The more difficult task is to keep the mass of the dilaton light compared to the dynamical scale, Lambda ~ 4 pi f, of the theory. In generic, non-supersymmetric theories one would expect the dilaton mass to be similar to Lambda. The mass of the dilaton can only be lowered at the price of some percent level (or worse) tuning and/or additional dynamical assumptions: one needs to suppress the contribution of the condensate to the vacuum energy (which would lead to a large dilaton quartic coupling), and to allow only almost marginal deformations of the CFT.