Custodial leptons and Higgs decays

  • Adrián Carmona
  • Florian Goertz


We study the effects of extended fermion sectors, respecting custodial symmetry, on Higgs production and decay. The resulting protection for the Zb L b L and Zτ R τ R decays allows for potentially interesting signals in Higgs physics, while maintaining the good agreement of the Standard Model with precision tests, without significant fine-tuning. Although being viable setups on their own, the models we study can particularly be motivated as the low energy effective theories of the composite Higgs models MCHM5 and MCHM10 or the corresponding gauge-Higgs unification models. The spectra can be identified with the light custodians present in these theories. These have the potential to describe the relevant physics in their fermion sectors in a simplified and transparent way. In contrast to previous studies of composite models, we consider the impact of a realistic lepton sector on the Higgs decays. We find significant modifications in the decays to τ leptons and photons due to the new leptonic resonances. While from a pure low energy perspective an enhancement of the channel pp → h → γγ turns out to be possible, if one considers constraints on the parameters from the full structure of the composite models, the decay mode into photons is always reduced. We also demonstrate that taking into account the non-linearity of the Higgs sector does not change the qualitative picture for the decays into τ leptons or photons in the case of the dominant Higgs production mechanism.


Higgs Physics Beyond Standard Model Technicolor and Composite Models 


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Copyright information

© SISSA, Trieste, Italy 2013

Authors and Affiliations

  1. 1.Institute for Theoretical PhysicsETH ZurichZurichSwitzerland

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