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Lepton flavor violating Higgs boson decays at the Compact Linear Collider

Francisca Garay2,3,*, Gabriel Vega2,3, and Philipp Roloff1

  • *Contact author: fmgaray@cern.ch
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Phys. Rev. D 114, 072013 – Published 29 October, 2026

DOI: https://doi.org/10.1103/ym6v-19b2

Abstract

Lepton flavor violating decays of the Higgs boson h could appear in scenarios beyond the Standard Model of particle physics. In this article, we study the sensitivity of a future Compact Linear Collider, operating in e+e− collisions, to such processes, namely, h→eμ, h→τμ, and h→eτ. In the absence of any observation, 95% CL upper limits in the region of 10−4 to 10−5 could be placed on the branching fractions of these processes, assuming integrated luminosities of 4  ab−1 at s=1.4  TeV and 5  ab−1 at s=3  TeV.

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References (54)

  1. The ATLAS Collaboration, Observation of a new particle in the search for the standard model Higgs boson with the ATLAS detector at the LHC, Phys. Lett. B 716, 1 (2012).
  2. The CMS Collaboration, Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC, Phys. Lett. B 716, 30 (2012).
  3. F. Englert and R. Brout, Broken symmetry and the mass of gauge vector mesons, Phys. Rev. Lett. 13, 321 (1964).
  4. P. W. Higgs, Broken symmetries, massless particles and gauge fields, Phys. Lett. 12, 132 (1964).
  5. G. Guralnik, C. Hagen, and T. Kibble, Global conservation laws and massless particles, Phys. Rev. Lett. 13, 585 (1964).
  6. J. D. Bjorken and S. Weinberg, Mechanism for non conservation of muon number, Phys. Rev. Lett. 38, 622 (1977).
  7. J. L. Diaz-Cruz and J. J. Toscano, Lepton flavor violating decays of Higgs bosons beyond the standard model, Phys. Rev. D 62, 116005 (2000).
  8. M. Arana-Catania, E. Arganda, and M. J. Herrero, Non-decoupling SUSY in LFV Higgs decays: A window to new physics at the LHC, J. High Energy Phys. 09 (2013) 160; 10 (2015) 192(E).
  9. A. Arhrib, Y. Cheng, and O. C. W. Kong, Comprehensive analysis on lepton flavor violating Higgs boson to μτ decay insupersymmetry without R parity, Phys. Rev. D 87, 015025 (2013).
  10. D. Aloni, Y. Nir, and E. Stamou, Large BR(h→τμ) in the MSSM?, J. High Energy Phys. 04 (2016) 162.
  11. K. Agashe and R. Contino, Composite Higgs-mediated flavor-changing neutral current, Phys. Rev. D 80, 075016 (2009).
  12. A. Azatov, M. Toharia, and L. Zhu, Higgs mediated flavor changing neutral currents in warped extra dimensions, Phys. Rev. D 80, 035016 (2009).
  13. H. Ishimori et al., Non-Abelian discrete symmetries in particle physics, Prog. Theor. Phys. Suppl. 183, 1 (2010).
  14. G. Perez and L. Randall, Natural neutrino masses and mixings from warped geometry, J. High Energy Phys. 01 (2009) 077.
  15. M. E. Albrecht, M. Blanke, A. J Buras, B. Duling, and K. Gemmler, Electroweak and flavour structure of a warped extra dimension with custodial protection, J. High Energy Phys. 09 (2009) 064.
  16. A. Goudelis, O. Lebedev, and J. h. Park, Higgs-induced lepton flavor violation, Phys. Lett. B 707, 369 (2012).
  17. D. McKeen, M. Pospelov, and A. Ritz, Modified Higgs branching ratios versus CP and lepton flavor violation, Phys. Rev. D 86, 113004 (2012).
  18. BABAR Collaboration, Evidence for an excess of B¯→D(*)τ−ντ¯ decays, Phys. Rev. Lett. 109, 101802 (2012).
  19. LHCb Collaboration, Measurement of the ratio of the B0→D*−τ+ντ and B0→D*−μ+νμ branching fractions using three-prong τ-lepton decays, Phys. Rev. Lett. 120, 171802 (2018).
  20. LHCb Collaboration, Measurement of the ratio of branching fraction B(B¯0→D*+τ−ντ¯)/B(B¯0→D*+μ−νμ¯), Phys. Rev. Lett. 115, 111803 (2015).
  21. P. Ko, Y. Omura, Y. Shigekami, and C. Yu, LHCb anomaly and B physics in flavored Z′ models with flavored Higgs doublets, Phys. Rev. D 95, 115040 (2017).
  22. A. Carmona and F. Goertz, Lepton flavor and non-universality from minimal composite Higgs setups, Phys. Rev. Lett. 116, 251801 (2016).
  23. F. J. Botella, G. C. Branco, M. Nebot, and M. N. Rebelo, Flavour-changing Higgs couplings in a class of two Higgs doublet models, Eur. Phys. J. C 76, 161 (2016).
  24. LHCb Collaboration, Tests of lepton universality using B0→Ks0ℓ+ℓ− and B+→K*+ℓ+ℓ− decays, Phys. Rev. Lett. 128, 191802 (2022).
  25. LHCb Collaboration, Measurement of the branching fraction ratio RK at large dilepton invariant mass, J. High Energy Phys. 07 (2025) 198.
  26. The ATLAS Collaboration, Searches for lepton-flavour-violating decays of the Higgs boson into eτ and μτ in s=13  TeV  pp collisions with the ATLAS detector, J. High Energy Phys. 07 (2023) 166.
  27. The CMS Collaboration, Search for lepton-flavor violating decays of the Higgs boson in the μτ and eτ final states in proton-proton collisions at s=13  TeV, Phys. Rev. D 104, 032013 (2021).
  28. The ATLAS Collaboration, Search for the Higgs boson decays h→μμ and h→eμ in pp collisions at s=13  TeV with the ATLAS detector, Phys. Lett. B 801, 135148 (2020).
  29. Q. Qin, Q. Li, C.-D. L, F.-S. Yu, and S.-H. Zhou, Charged lepton flavour violating Higgs decays at future e+e− colliders, Eur. Phys. J. C 78, 835 (2018).
  30. P. Sriling et al., Searching for lepton flavor violating decays of the Higgs boson into μτ, eτ, and eμ final states at FCC-ee, arXiv:2605.30971.
  31. J. Adam et al., New Constraint on the existence of the μ→eγ decay, Phys. Rev. Lett. 110, 201801 (2013).
  32. R. Harnik, J. Kopp, and J. Zupan, Flavor violating Higgs decays, J. High Energy Phys. 03 (2013) 026.
  33. G. Blankenburg, J. Ellis, and G. Isidori, Flavour-changing decays of a 125 GeV Higgs-like particle, Phys. Lett. B 712, 386 (2012).
  34. The CLICdp Collaboration, Higgs physics at the CLIC electron-positron linear collider, Eur. Phys. J. C 77, 475 (2017).
  35. The CLIC and CLICdp Collaborations, Updated baseline for a staged compact linear collider, Report No. CERN-2016-004, CERN, Geneva, 10.5170/CERN-2016-004.
  36. The CLIC and CLICdp Collaborations, The Compact Linear Collider (CLIC)—2018 Summary Report, 10.23731/CYRM-2018-002.
  37. A. Robson and P. Roloff, Updated CLIC luminosity staging baseline and Higgs coupling prospects, Report No. CLICdp-Note-2018-002, CERN, Geneva, https://cds.cern.ch/record/2645352/.
  38. M. Aicheler et al., A multi-TeV linear collider based on CLIC technology: CLIC conceptual design report, Report No. CERN-2012-007, CERN, Geneva, https://cds.cern.ch/record/1500095.
  39. H. Abramowicz et al., The international linear collider technical design report—volume 4: Detectors, Report No. ILC-REPORT-2013-040, High Energy Accelerator Research Organization (KEK), Tsukuba, https://cds.cern.ch/record/1601969?ln=en.
  40. J. Marshall, A. Munnich, and M. Thomson, Performance of particle flow calorimetry at CLIC, Nucl. Instrum. Methods Phys. Res., Sect. A 700, 153 (2013).
  41. Linssen et al., Physics and detectors at CLIC: CLIC conceptual design report, arXiv:1202.5940.
  42. W. Kilian, T. Ohl, and J. Reuter, WHIZARD: Simulating multi-particle processes at LHC and ILC, Eur. Phys. J. C 71, 1742 (2011).
  43. M. Skrzypek and S. Jadach, Exact and approximate solutions for the electron nonsinglet structure function in QED, Z. Phys. C 49, 577 (1991).
  44. T. Sjostrand, S. Mrenna, and P. Z. Skands, PYTHIA 6.4 physics and manual, J. High Energy Phys. 05 (2006) 026.
  45. G. Alexander et al. (OPAL Collaboration), A comparison of b and uds quark jets to gluon jets, Physica C 69, 543 (1995).
  46. Z. Was, TAUOLA the library for tau lepton decay, and KKMC / KORALB / KORALZ /... status report, Nucl. Phys. B, Proc. Suppl. 98, 96 (2001).
  47. A. Robson and P. Roloff, CLIC Higgs coupling prospects with 100 Hz operation, arXiv:2503.21857v1.
  48. Arominski et al., A detector for CLIC: Main parameters and performance, arXiv:1812.07337.
  49. F. Gaede, marlin and LCCD: Software tools for the ILC, Nucl. Instrum. Methods Phys. Res., Sect. A 559, 177 (2006).
  50. M. Thomson, Particle flow calorimetry and the PandoraPFA algorithm, Nucl. Instrum. Methods Phys. Res., Sect. A 611, 25 (2009).
  51. J. S. Marshall and M. A. Thomson, The Pandora software development kit for pattern recognition, Eur. Phys. J. C 75, 439 (2015).
  52. A. Hoecker et al., TMVA—toolkit for multivariate data analysis, arXiv:physics/0703039.
  53. G. Cowan, K. Cranmer, E. Gross, and O. Vitells, Asymptotic formulae for likelihood-based tests of new physics, Eur. Phys. J. C 71, 1554 (2011).
  54. A. Muennich, TauFinder: A reconstruction algorithm for τ leptons at linear colliders, Report No. LCD-Note-2010-009, http://cds.cern.ch/record/1443551.

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Phys. Rev. D 114, 072013– Published 29 October, 2026
  • Received 11 May 2026
  • Accepted 8 October 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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