Collider constraints on dark mediators

TL;DR

This paper investigates collider constraints on a QCD-like dark sector with a focus on mediator mass limits across various dark meson lifetimes, considering flavor structures and comparing with direct detection bounds.

Contribution

It provides the first comprehensive analysis of collider constraints on dark mediators across the full range of dark meson lifetimes, including flavored scenarios.

Findings

Collider searches constrain mediator mass for various dark meson lifetimes.

Flavor structure affects dark pion distinguishability and search sensitivity.

Collider bounds are stronger when coupling to first-generation quarks is suppressed.

Abstract

We explore the constraints current collider searches place on a QCD-like dark sector. A combination of multi-jet, multi-jet plus missing energy and emerging jets searches is used to derive constraints on the mediator mass across the full range of the dark meson lifetimes for the first time. The dark sector inherits a flavour structure from the coupling between the dark quarks and the SM quarks through the mediator. When this is taken into account, the differently flavoured dark pions become distinguishable through their lifetime. We show that also in these cases the above mentioned searches remain sensitive, and we obtain limits on the mediator mass also for the flavoured scenario. We then contrast the constraints from collider searches with direct detection bounds on the dark matter candidate itself in both the flavoured and unflavoured scenario. Using a simple prescription it becomes possible to display all constraints in the dark matter and mediator mass plane. Constraints from direct detection tend to be stronger than the collider constraints, unless the coupling to the first generation quarks is suppressed, in which case the collider searches place the most stringent limits on the parameter space.