Abstract
We study the phenomenological viability of chiral extensions of the Standard Model, with new chiral fermions acquiring their mass through interactions with a single Higgs. We examine constraints from electroweak precision tests, Higgs physics and direct searches at the LHC. Our analysis indicates that purely chiral scenarios are perturbatively excluded by the combination of Higgs coupling measurements and LHC direct searches. However, allowing for a partial contribution from vector-like masses opens up the parameter space and non-decoupled exotic leptons could account for the observed 2σ deviation in h → Zγ. This scenario will be further tested in the high-luminosity phase of the LHC.
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Acknowledgments
We thank Michele Frigerio for useful discussions. The work of LDL, MN and CT is supported by the by the Italian Ministry of University and Research (MUR) via the PRIN 2022 project n. 2022K4B58X — AxionOrigins. The work of LDL is also supported by the European Union — NextGenerationEU and by the University of Padua under the 2021 STARS Grants@Unipd programme (Acronym and title of the project: CPV-Axion — Discovering the CP-violating axion), the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement n. 101086085 — ASYMMETRY and the INFN Iniziative Specifica APINE.
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Barducci, D., Di Luzio, L., Nardecchia, M. et al. Closing in on new chiral leptons at the LHC. J. High Energ. Phys. 2023, 154 (2023). https://doi.org/10.1007/JHEP12(2023)154
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DOI: https://doi.org/10.1007/JHEP12(2023)154