Higgs-Dilaton Cosmology: An inflation - dark energy connection and forecasts for future galaxy surveys

TL;DR

This paper explores the Higgs-Dilaton cosmological model, deriving its unique predictions linking inflation and dark energy, and assesses how future galaxy surveys can distinguish it from standard cosmological models.

Contribution

It provides an alternative derivation of the model's consistency relations and forecasts the potential of upcoming surveys to test this minimalistic scale-invariant scenario.

Findings

Future surveys like Euclid and SKA2 can differentiate Higgs-Dilaton cosmology from ΛCDM and wCDM.

The model predicts measurable relations between inflationary parameters and dark energy.

Current data constraints are consistent with the model's predictions.

Abstract

The Higgs-Dilaton model is a scale-invariant extension of the Standard Model non-minimally coupled to gravity and containing just one additional degree of freedom on top of the Standard Model particle content. This minimalistic scenario predicts a set of measurable consistency relations between the inflationary observables and the dark-energy equation-of-state parameter. We present an alternative derivation of these consistency relations that highlights the connections and differences with the $\alpha$-attractor scenario. We study in how far these constraints allow to distinguish the Higgs-Dilaton model from $\Lambda$CDM and $w$CDM cosmologies. To this end we first analyze existing data sets using a Markov Chain Monte Carlo approach. Second, we perform forecasts for future galaxy surveys using a Fisher matrix approach, both for galaxy clustering and weak lensing probes. Assuming that the best fit values in the different models remain comparable to the present ones, we show that both Euclid- and SKA2-like missions will be able to discriminate a Higgs-Dilaton cosmology from $\Lambda$CDM and $w$CDM.