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arXiv · 2611.03893

Searching for Long-Lived Dark Scalars with MAPP-1 and MAPP-2 at the HL-LHC

Shafakat Arifeen·James Pinfold·Pierre-Philippe A. Ouimet·Michael Staelens
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Abstract

Feebly interacting particles (FIPs) arise generically in dark-sector extensions of the Standard Model (SM). Among the simplest and most theoretically motivated such candidates is a dark scalar that mixes with the SM Higgs boson, acting as a mediator between the dark sector and the SM. For sufficiently small mixing, such a dark scalar manifests at collider experiments as a long-lived particle with a macroscopic decay length---a signature to which conventional general-purpose detectors have limited sensitivity. The MoEDAL-MAPP experiment is a dedicated search facility at the Large Hadron Collider (LHC) targeting long-lived FIPs as avatars of physics beyond the SM. We present $95\%$ confidence-level background-free sensitivity projections for the MAPP-1 and MAPP-2 detectors at the High-Luminosity LHC to Higgs-portal dark scalars produced via rare $B$-meson decays and exotic Higgs boson decays. Our results establish the proposed MAPP-2 detector as a complementary probe of feebly-coupled dark scalars, with sensitivity to lifetimes beyond the reach of existing collider searches.

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Shafakat Arifeen, James Pinfold, Pierre-Philippe A. Ouimet, Michael Staelens. 2026-11-02. Searching for Long-Lived Dark Scalars with MAPP-1 and MAPP-2 at the HL-LHC. https://arxiv.org/abs/2611.03893

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