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Investigating the leptonic couplings of doubly charged scalars at the muon collider

Nivedita Ghosh1,*, Santosh Kumar Rai2,†, Tousik Samui3,‡, and Agnivo Sarkar2,§

  • *Contact author: nivedita.ghosh@ipmu.jp
  • †Contact author: skrai@hri.res.in
  • ‡Contact author: tousiks@imsc.res.in
  • §Contact author: agnivosarkar@hri.res.in
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Phys. Rev. D 113, 055048 – Published 26 March, 2026

DOI: https://doi.org/10.1103/jbq9-jy42

Abstract

We study the lepton flavor conserving and violating couplings of a doubly charged scalar at a 3 TeV muon collider. Using a model-independent Lagrangian, we analyze the ee, μμ, and ττ final states mediated by the doubly charged scalar to probe individual couplings to μe, μμ, and μτ. We find that for a doubly charged scalar of mass greater than 1 TeV and O(1) couplings, we achieve high signal significance in these channels. We delineate the collider’s sensitivity in the mass-coupling plane, highlighting the extensive reach of the muon collider in probing these couplings far beyond the current experimental limits. We also propose an angular distribution variable to discriminate between the exchange of a doubly charged scalar from that of a neutral scalar, which gives identical signals.

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Phys. Rev. D 113, 055048– Published 26 March, 2026
  • Received 18 June 2025
  • Accepted 27 February 2026
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