Long-lived Dark Higgs and Inelastic Dark Matter at Belle II

TL;DR

This paper explores the potential of Belle II to detect long-lived dark Higgs particles and inelastic dark matter through displaced vertex signatures, highlighting the importance of a displaced vertex trigger for enhanced sensitivity.

Contribution

It introduces a novel search strategy for long-lived dark Higgs and inelastic dark matter at Belle II, emphasizing displaced vertices and missing momentum signatures.

Findings

Belle II can be highly sensitive to dark Higgs and inelastic dark matter signals.

Displaced vertex triggers significantly improve detection prospects.

The study provides a new approach to probing dark sector particles.

Abstract

Inelastic dark matter is an interesting scenario for light thermal dark matter which is fully consistent with all cosmological probes as well as direct and indirect dark matter detection. The required mass splitting between dark matter $\chi_1$ and its heavier twin $\chi_2$ is naturally induced by a dark Higgs field which also provides a simple mechanism to give mass to the dark photon $A'$ present in the setup. The corresponding dark Higgs boson $h'$ is naturally the lightest dark sector state and therefore decays into Standard Model particles via Higgs mixing. In this work we study signatures with displaced vertices and missing momentum at Belle II, arising from dark Higgs particles produced in association with dark matter. We find that Belle II can be very sensitive to this scenario, in particular if a displaced vertex trigger is available in the near future.