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Roman Pasechnik

Senior lecturer

Typical working day..

Collider signatures of vector-like fermions from a flavor symmetric model


  • Cesar Bonilla
  • A. E.Cárcamo Hernández
  • João Gonçalves
  • Felipe F. Freitas
  • António P. Morais
  • R. Pasechnik

Summary, in English

We propose a model with two Higgs doublets and several SU(2) scalar singlets with a global non-Abelian flavor symmetry Q6× Z2. This discrete group accounts for the observed pattern of fermion masses and mixing angles after spontaneous symmetry breaking. In this scenario only the third generation of fermions get their masses as in the Standard Model (SM). The masses of the remaining fermions are generated through a seesaw-like mechanism. To that end, the matter content of the model is enlarged by introducing electrically charged vector-like fermions (VLFs), right handed Majorana neutrinos and several SM scalar singlets. Here we study the processes involving VLFs that are within the reach of the Large Hadron Collider (LHC). We perform collider studies for vector-like leptons (VLLs) and vector-like quarks (VLQs), focusing on double production channels for both cases, while for VLLs single production topologies are also included. Utilizing genetic algorithms for neural network optimization, we determine the statistical significance for a hypothetical discovery at future LHC runs. In particular, we show that we can not safely exclude VLLs for masses greater than 200 GeV. For VLQ’s in our model, we show that we can probe their masses up to 3.8 TeV, if we take only into account the high-luminosity phase of the LHC. Considering Run-III luminosities, we can also exclude VLQs for masses up to 3.4 TeV. We also show how the model with predicted VLL masses accommodates the muon anomalous magnetic moment.


  • Theoretical Particle Physics

Publishing year





Journal of High Energy Physics





Document type

Journal article




  • Subatomic Physics


  • Beyond Standard Model
  • Hadron-Hadron scattering (experiments)
  • vector-like quarks




  • ISSN: 1029-8479