A New Probe for Long-Lived Particles at Higgs Factories: Displaced Photons in the Hadronic Calorimeter

Fuente: arXiv
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Main Authors: Jiang, Zhicheng, Li, Hengne, Liang, Jin-Han
Format: Preprint
Published: 2025
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author Jiang, Zhicheng
Li, Hengne
Liang, Jin-Han
author_facet Jiang, Zhicheng
Li, Hengne
Liang, Jin-Han
contents The search for dark matter and other photon-portal long-lived particles (LLPs) at electron-positron colliders often relies on the mono-photon signature. At future Higgs factories operating at the $Z$-pole, this approach faces a critical challenge: the irreducible background from $e^+e^- \to ν\barνγ$ becomes overwhelming. We propose a novel strategy that overcomes this limitation by searching for displaced photons from LLP decays within the barrel of the hadronic calorimeter. This signature exploits the architectural shielding of the detector to create a nearly background-free environment. Our analysis demonstrates exceptional sensitivity to LLPs with decay lengths from $\sim$1 to $10^6$ meters, improving upon conventional searches by up to one order of magnitude for benchmark photon-portal models.
format Preprint
id arxiv_https___arxiv_org_abs_2510_26649
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A New Probe for Long-Lived Particles at Higgs Factories: Displaced Photons in the Hadronic Calorimeter
Jiang, Zhicheng
Li, Hengne
Liang, Jin-Han
High Energy Physics - Phenomenology
High Energy Physics - Experiment
The search for dark matter and other photon-portal long-lived particles (LLPs) at electron-positron colliders often relies on the mono-photon signature. At future Higgs factories operating at the $Z$-pole, this approach faces a critical challenge: the irreducible background from $e^+e^- \to ν\barνγ$ becomes overwhelming. We propose a novel strategy that overcomes this limitation by searching for displaced photons from LLP decays within the barrel of the hadronic calorimeter. This signature exploits the architectural shielding of the detector to create a nearly background-free environment. Our analysis demonstrates exceptional sensitivity to LLPs with decay lengths from $\sim$1 to $10^6$ meters, improving upon conventional searches by up to one order of magnitude for benchmark photon-portal models.
title A New Probe for Long-Lived Particles at Higgs Factories: Displaced Photons in the Hadronic Calorimeter
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
url https://arxiv.org/abs/2510.26649