Journal of High Energy Physics

, 2019:139 | Cite as

Shedding light on top partner at the LHC

  • Haider Alhazmi
  • Jeong Han KimEmail author
  • Kyoungchul Kong
  • Ian M. Lewis
Open Access
Regular Article - Theoretical Physics


We investigate the sensitivity of the 14 TeV LHC to pair-produced top partners (T) decaying into the Standard Model top quark (t) plus either a gluon (g) or a photon (γ). The decays Ttg and Ttγ can be dominant when the mixing between the top partner and top quark are negligible. In this case, the conventional decays TbW , TtZ, and Tth are highly suppressed and can be neglected. We take a model-independent approach using effective operators for the T -t-g and T -t-γ interactions, considering both spin- \( \frac{1}{2} \) and spin- \( \frac{3}{2} \) top partners. We perform a semi-realistic simulation with boosted top quark tagging and an appropriate implementation of a jet-faking-photon rate. Despite a simple dimensional analysis indicating that the branching ratios BR(Ttγ) ≪ BR(Ttg) due to the electric-magnetic coupling being much smaller than the strong force coupling, our study shows that the LHC sensitivity to \( T\overline{T}\to t\overline{t}\gamma g \) is more significant than the sensitivity to \( T\overline{T}\to t\overline{t} gg \). This is due to much smaller backgrounds attributed to the isolated high-pT photon. We find that with these decay channels and 3 ab−1 of data, the LHC is sensitive to top partner masses mT ≲ 1.4-1.8 TeV for spin- \( \frac{1}{2} \) and spin- \( \frac{3}{2} \) top partners, respectively.


Beyond Standard Model Higgs Physics 


Open Access

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Copyright information

© The Author(s) 2019

Authors and Affiliations

  • Haider Alhazmi
    • 1
    • 2
  • Jeong Han Kim
    • 1
    Email author
  • Kyoungchul Kong
    • 1
  • Ian M. Lewis
    • 1
  1. 1.Department of Physics and AstronomyUniversity of KansasLawrenceU.S.A.
  2. 2.Department of PhysicsJazan UniversityJazanSaudi Arabia

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