arXiv subjects

Wanyun Chen

Publications and source records attributed to Wanyun Chen.

2 recordsLinked to original sources

arXiv2026

Exploring muonphilic dark matter with the $Z_2$-even mediator at muon colliders

The Galactic Center GeV Excess (GCE) remains a compelling but enigmatic signal from the inner region of our galaxy. Muonphilic dark matter (DM), which couples exclusively to muons via a new mediator, provides a viable explanation for the GCE and relic density while naturally evading constraints from direct detection, collider searches and other multi-messenger observations. Based on the viable non-resonant parameter space identified in previous global fits, we perform a comprehensive study exploring the prospects for discovering such muonphilic DM in the context of a future $3$ TeV muon collider, focusing on simplified models with a $Z_2$-even mediator. Four distinct search strategies are investigated: visible on-shell mediator decays ($μ^{+}μ^{-}γ$ final state), invisible on-shell mediator decays (mono-photon plus missing energy), mono-photon production via off-shell mediators, and vector boson fusion production.Through a detailed signal-background analysis using cut-and-count methods, we project the exclusion limits at $95\%$ confidence level for seven representative models across a wide range of mediator masses. Our results demonstrate that the projected limits cover a significant portion of the viable parameter space that explains the GCE, establishing a muon collider as a decisive machine for testing the muonphilic DM hypothesis.

hep-ph↗

arXiv2025

Probing gluons-enriched dark jets from Higgs boson exotic decays at the LHC

The dark sector may possess a rich structure yet to be uncovered, and a QCD-like dark sector with GeV-scale dark hadrons can yield novel signatures at the Large Hadron Collider (LHC). In this work, we focus on a light singlet pseudoscalar mediator that connects the QCD-like dark sector to the Standard Model (SM) sector via the Higgs portal. Notably, when the lightest unstable dark meson has a mass of approximately $3$ GeV, it predominantly decays into a pair of gluons and behaves as a long-lived particle, a scenario that has received relatively little attention. We consider various Higgs production channels at the LHC and investigate two processes for generating dark mesons: (1) the cascade decay of the Higgs boson into a pair of light pseudoscalar mediators, which subsequently decay into four dark mesons; and (2) the dark shower and hadronization process whereby the Higgs boson decays into a pair of dark quarks that subsequently evolve into dark mesons. These processes give rise to novel gluon-rich dark jets composed of long-lived dark mesons. Notably, we find that appropriate trigger selection constitutes a crucial factor for detecting these signal signatures in both tracker system and CMS muon system. At the high-luminosity LHC, the exotic Higgs branching ratio to cascade decays (dark showers) can be constrained below $\mathcal{O}(10^{-5}-10^{-1})$ [$\mathcal{O}(10^{-5}-10^{-2})$] for dark meson proper lifetimes $cτ$ ranging from $1$ mm to $100$ m.

hep-ph↗