New physics models facing lepton flavor violating Higgs decays at the percent level

  • Ilja Doršner
  • Svjetlana Fajfer
  • Admir Greljo
  • Jernej F. Kamenik
  • Nejc Košnik
  • Ivan Nišandžić
Open Access
Regular Article - Theoretical Physics


We speculate about the possible interpretations of the recently observed excess in the hτμ decay. We derive a robust lower bound on the Higgs boson coupling strength to a tau and a muon, even in presence of the most general new physics affecting other Higgs properties. Then we reevaluate complementary indirect constraints coming from low energy observables as well as from theoretical considerations. In particular, the tentative signal should lead to τμγ at rates which could be observed at Belle II. In turn we show that, barring fine-tuned cancellations, the effect can only be accommodated within models with an extended scalar sector. These general conclusions are demonstrated using a number of explicit new physics models. Finally we show how, given the hτμ signal, the current and future searches for μ and μe nuclear conversions unambiguously constrain the allowed rates for hτe.


Higgs Physics Rare Decays Beyond Standard Model 


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Copyright information

© The Author(s) 2015

Authors and Affiliations

  • Ilja Doršner
    • 1
    • 2
  • Svjetlana Fajfer
    • 2
    • 3
  • Admir Greljo
    • 4
    • 5
  • Jernej F. Kamenik
    • 2
    • 3
  • Nejc Košnik
    • 2
    • 3
  • Ivan Nišandžić
    • 6
  1. 1.University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture in Split (FESB)SplitCroatia
  2. 2.Jožef Stefan InstituteLjubljanaSlovenia
  3. 3.Department of Physics, University of LjubljanaLjubljanaSlovenia
  4. 4.Physik-InstitutUniversität ZürichZürichSwitzerland
  5. 5.Department of PhysicsUniversity of SarajevoSarajevoBosnia and Herzegovina
  6. 6.Institut für PhysikTechnische Universität DortmundDortmundGermany

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