Dilaton at the LHC: Complementary Probe of Composite Higgs

TL;DR

This paper investigates the potential of the dilaton as a detectable signature of composite Higgs models at the LHC, analyzing current data and future prospects, and highlighting its complementarity to Higgs coupling measurements.

Contribution

It provides a detailed analysis of dilaton signatures in composite Higgs models, connecting dilaton properties with Higgs potential parameters and assessing experimental sensitivities.

Findings

Dilaton mass sensitivity up to ~3 TeV in current experiments.

Dilaton searches can be as sensitive or more than Higgs coupling measurements.

Dilaton detection offers a complementary probe of Higgs compositeness.

Abstract

The dilaton is predicted in various extensions of the standard model containing sectors with an approximate spontaneously-broken conformal invariance. As a Goldstone boson of a spontaneously broken symmetry, the dilaton can naturally be one of the lightest new physics particles, and therefore may be the first new physics imprint observed in collider experiments. In particular, it can arise in composite Higgs models which are often assumed to have approximate conformal invariance in the UV. The dilaton is then a composite state, generated by the same sector that produces the Higgs. We continue the exploration of composite dilaton signatures at the LHC, using the latest experimental data and analysing the future detection prospects. We elaborate on the connection of the dilaton properties with the properties of the Higgs potential, clarifying in particular the relation between the scale relevant for electroweak fine tuning and the scale controlling the dilaton couplings. This relation is then used to derive the experimental sensitivity to the dilaton in natural composite Higgs scenarios, which reaches ~3 TeV in dilaton mass for generic parameter choices. At the same time, we show that dilaton searches are a complementary direction to probe Higgs boson compositeness, with the sensitivity comparable or exceeding that of Higgs coupling measurements.