Abstract
LHC results do not confirm conventional natural solutions to the Higgs mass hierarchy problem, motivating alternative interpretations where a hierarchically small weak scale is generated from a dimension-less quantum dynamics. We propose weakly and strongly-coupled models where the field that breaks classical scale invariance giving mass to itself and to the Higgs is identified with a possible new resonance within the LHC reach. As an example, we identify such resonance with the 750 GeV diphoton excess recently reported by ATLAS and CMS. Such models can be extrapolated up to the Planck scale, provide Dark Matter candidates and eliminate the SM vacuum instability.
Highlights
Small, classical scale invariance is an approximate symmetry of the model, otherwise it is just the requirement that the masses are dynamically generated
References [71, 72] tried to incorporate the diphoton hinted by ATLAS and CMS in the weakly-coupled framework; in both cases couplings are so large that the attempted models hit Landau poles just above the weak scale, such that no hierarchy is dynamically generated
We proposed dimension-less models where a new resonance decaying into two photons dynamically breaks scale invariance, generating a weak scale hierarchically smaller than the Planck scale
Summary
Various extensions of the SM where the weak scale is generateda la Coleman-Weinberg have been proposed in the literature. Recasting LHC searches for similar objects [77], we estimate a bound MX >∼ 1.0 (1.2) TeV on their masses for N = 3 (10) We assume that such extra Yukawa couplings are small enough that we can neglect their contributions to the RGE. This example has MX = 1.6 TeV, Γγγ 4.4 × 10−7M , Γgg 4.2 × 10−6M In both cases the SU(N ) gauge constant becomes relatively large at the diphoton scale such that the couplings (in particular λXS) have a fast running; we tried to include such corrections by renormalising couplings at appropriate scales
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