Search for single production of vectorlike top partners through

The vectorlike top partners are potential signature of some new physics beyond the Standard Model at the TeV scale. In this paper, we propose to search for the vectorlike T quark with charge 2/3 in the framework of a simplified model where the top partners only couples with the third generation of Standard Model quarks. We investigate the observability for electroweak production of a vectorlike T quark in association with a standard model bottom quark through the process $$pp \rightarrow T\bar{b}j$$ with the subsequent decay mode of $$T\rightarrow t(\rightarrow b W^+\rightarrow b \ell ^{+} \nu _{\ell })h( \rightarrow \gamma \gamma )$$, at the proposed High Energy Large Hadron Collider (HE-LHC) and Future Circular Collider in hadron-hadron mode (FCC-hh) including the realistic detector effects. The 95% confidence level excluded regions and the $$5\sigma $$ discovery reach in the parameter plane of $$\kappa _{T}-m_T$$, are respectively obtained at the HE-LHC with the integrated luminosity of 15 ab$$^{-1}$$ and the FCC-hh with the integrated luminosity of 30 ab$$^{-1}$$. We also analyze the projected sensitivity in terms of the production cross section times branching fraction at the HE-LHC and FCC-hh