Emerging jet probes of strongly interacting dark sectors

TL;DR

This paper investigates how emerging jets from strongly interacting dark sectors can be detected at colliders, reinterpreting CMS search results to set bounds on dark sector models and projecting future sensitivities.

Contribution

It provides a reinterpretation of CMS emerging jet searches for various dark sector models mediated by the Higgs, and projects future collider sensitivities to exotic Higgs decays into dark quarks.

Findings

Emerging jets can be the leading probe for certain dark sector models.

Current LHC data can exclude about 20% exotic Higgs branching ratio into dark quarks.

Future HL-LHC runs could detect branching ratios below 1%.

Abstract

A strongly interacting dark sector can give rise to a class of signatures dubbed dark showers, where in analogy to the strong sector in the Standard Model, the dark sector undergoes its own showering and hadronization, before decaying into Standard Model final states. When the typical decay lengths of the dark sector mesons are larger than a few centimeters (and no larger than a few meters) they give rise to the striking signature of emerging jets, characterized by a large multiplicity of displaced vertices. In this article we consider the general reinterpretation of the CMS search for emerging jets plus prompt jets into arbitrary new physics scenarios giving rise to emerging jets. More concretely, we consider the cases where the SM Higgs mediates between the dark sector and the SM, for several benchmark decay scenarios. Our procedure is validated employing the same model than the CMS emerging jet search. We find that emerging jets can be the leading probe in regions of parameter space, in particular when considering the so-called gluon-portal and dark photon-portal decay benchmarks. With the current 16.1 fb$^{-1}$ of luminosity this search can exclude down to ${\cal O} (20) \% $ exotic branching ratio of the SM Higgs, but a naive extrapolation to the 139 fb$^{-1}$ luminosity employed in the current model-independent, indirect bound of 16% would probe exotic branching ratios into dark quarks down to below 10%. Further extrapolating these results to the HL-LHC, we find that one can pin down exotic branching ratio values of 1%, which is below the HL-LHC expectations of 2.5$-$4%. We make our recasting code publicly available, as part of the LLP Recasting Repository.