Heavy dark matter through the dilaton portal

TL;DR

This paper investigates the constraints on a heavy dilaton coupled to dark matter, analyzing collider, direct detection, and unitarity bounds, and emphasizes the importance of gauge-invariant formulations and missing terms in effective theories.

Contribution

It provides a comprehensive re-examination of dilaton-dark matter models, including gauge-invariant treatment, correction of effective field theories, and new unitarity constraints, with projections for future colliders.

Findings

Current collider and detection data constrain heavy dilaton models.

Proper gauge-invariant formulations are crucial for accurate analysis.

Future colliders like HL-LHC and FCC can probe significant parameter space.

Abstract

We re-examine current and future constraints on a heavy dilaton coupled to a simple dark sector consisting of a Majorana fermion or a St\"uckelberg vector field. We include three different treatments of dilaton-Higgs mixing, paying particular attention to a gauge-invariant formulation of the model. Moreover, we also invite readers to re-examine effective field theories of vector dark matter, which we show are missing important terms. Along with the latest Higgs coupling data, heavy scalar search results, and dark matter density/direct detection constraints, we study the LHC bounds on the model and estimate the prospects of dark matter production at the future HL-LHC and 100 TeV FCC colliders. We additionally compute novel perturbative unitarity constraints involving vector dark matter, dilaton and gluon scattering.