Preprint
New physics in multi-lepton tau decays
ArXiv.org
Cornell University
04/01/2026
DOI: 10.48550/arxiv.2604.01465
Abstract
Dark particles with lepton-flavor-violating couplings to the tau lepton can induce rare neutrinolessτdecays with large final state multiplicities. We study models where transitions of the typeτ^(±)→ ℓ^(±) ϕ , withϕa light new particle, initiate a chain of decays in the dark sector that terminate with decays into electrons, muons, or pions. These decay cascades appear as rare five or even seven-bodyτdecays with multiple reconstructable resonances. We survey several representative models: kinetically mixed dark photon, gaugedLᵢ-Lⱼmodels, and other more exotic charge assignments such as chiralU(1)'extensions of the Standard Model. The main new ingredient is the possibility of flavor violation at very high scales. In these models, a number of channels that have not yet been searched for experimentally, such asτ→ 5μ ,τ→ 3μ 2e ,τ→ μ 4e , and hadronic channels likeτ→ μ 4π , typically dominate over the previously-considered signatures such asτ→ 3μ . While some of the models, such as the gaugedLᵢ-Lⱼones, also contain more challenging channels with missing energy due to decays to neutrinos, they can still be searched for via fully visible channels.
Details
- Title: Subtitle
- New physics in multi-lepton tau decays
- Creators
- Yohei EmaPatrick J FoxMatheus HostertTony MenzoMaxim PospelovAnupam RayJure Zupan
- Resource Type
- Preprint
- Publication Details
- ArXiv.org
- DOI
- 10.48550/arxiv.2604.01465
- ISSN
- 2331-8422
- Publisher
- Cornell University; Ithaca, New York
- Language
- English
- Date posted
- 04/01/2026
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9985147012702771
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