Darkonia at Colliders

TL;DR

This paper explores the potential collider signatures of dark matter bound states, called darkonia, across various models, highlighting unique decay patterns and detection prospects at LHC and Belle II.

Contribution

It systematically analyzes darkonium signatures in three models with different force carriers, revealing new decay channels and experimental signatures for collider searches.

Findings

Darkonium states can be stable or decay into dark-force carriers.

Distinctive signatures include displaced vertices and mixed missing energy with di-lepton/di-jet pairs.

Detection prospects are promising at LHC and Belle II.

Abstract

Dark matter may form bound states in a dark sector with an attractive force between two dark matter particles. Searches for dark matter at colliders can differ dramatically from routine searches if bound states, dubbed darkonia, are produced and decay into visible Standard-Model particles. In this work, we use three representative models with scalar, pseudo-scalar, and vector force carriers to map out the darkonium signatures at both high-energy and low-energy colliders. Some of the bound states can be stable due to generalized parity and charge-conjugation symmetries, while others decay into light dark-force carriers, which subsequently can decay at a displaced vertex. New signatures with a mix of missing energy and multiple di-lepton or di-jet vertices reconstructing intermediate darkonium resonances are within reach at the LHC and Belle II.