Dark Higgs-strahlung at Belle II: A distinctive dark sector signature with displaced vertices and missing energy

Fuente: arXiv
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Main Authors: Acanfora, Francesca, Kahlhoefer, Felix
Format: Preprint
Published: 2025
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author Acanfora, Francesca
Kahlhoefer, Felix
author_facet Acanfora, Francesca
Kahlhoefer, Felix
contents Dark photons with kinetic mixing are compelling mediators for the interactions between dark matter and Standard Model particles. While most experimental searches focus on fully visible or fully invisible decays of dark photons, we explore processes that involve dark Higgs-strahlung, i.e. the emission of a dark Higgs boson connected to the mass generation of the dark photon. If the dark Higgs boson is the lightest dark sector particle, it is expected to be long-lived and decay into Standard Model particles via Higgs mixing. At electron-positron colliders, dark Higgs-strahlung may occur either in isolation (leading to a single displaced vertex and missing energy) or accompanied by a photon from initial-state radiation. Both signatures offer distinctive kinematic features, such as peaks in photon energy or missing invariant mass, which enable efficient background suppression and enhances sensitivity beyond existing searches. Our study suggests that Belle II could significantly improve coverage of dark sector models by targeting this previously unexplored final state and that combining dark Higgs-strahlung events with and without additional photon offers great potential for reconstructing the properties of the dark sector.
format Preprint
id arxiv_https___arxiv_org_abs_2508_09247
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dark Higgs-strahlung at Belle II: A distinctive dark sector signature with displaced vertices and missing energy
Acanfora, Francesca
Kahlhoefer, Felix
High Energy Physics - Phenomenology
Dark photons with kinetic mixing are compelling mediators for the interactions between dark matter and Standard Model particles. While most experimental searches focus on fully visible or fully invisible decays of dark photons, we explore processes that involve dark Higgs-strahlung, i.e. the emission of a dark Higgs boson connected to the mass generation of the dark photon. If the dark Higgs boson is the lightest dark sector particle, it is expected to be long-lived and decay into Standard Model particles via Higgs mixing. At electron-positron colliders, dark Higgs-strahlung may occur either in isolation (leading to a single displaced vertex and missing energy) or accompanied by a photon from initial-state radiation. Both signatures offer distinctive kinematic features, such as peaks in photon energy or missing invariant mass, which enable efficient background suppression and enhances sensitivity beyond existing searches. Our study suggests that Belle II could significantly improve coverage of dark sector models by targeting this previously unexplored final state and that combining dark Higgs-strahlung events with and without additional photon offers great potential for reconstructing the properties of the dark sector.
title Dark Higgs-strahlung at Belle II: A distinctive dark sector signature with displaced vertices and missing energy
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2508.09247