Search strategies for TeV scale fermionic top partners with charge 2/3

Abstract

Searches for fermionic top partners at the TeV scale will bring forward a new final state kinematic regime and event topologies, where Run I search strategies will inevitably fail. We propose concrete search strategies for singly produced charge 2/3 fermionic top partners ($T'$) adequate for LHC Run II. Our analysis spans over all of the $T'$ decay modes ($i.e.$ $tZ$, $th$ and $Wb$) where we present detailed discussion of the search performances, signal efficiencies and backgrounds rates. Our LHC Run II search proposals utilize signatures with large missing energy and leptons, as well as jet substructure observables for tagging of boosted heavy SM states, customized $b$-tagging tactics and forward jet tagging. We analyze the prospects for discovery and exclusion of $T'$ models within the framework of partially composite quarks at the LHC Run II. Our results show that the LHC Run II has good prospects for observing $T'$ models which predict single production cross section of $\sigma_{T'} \sim 70 -140 \, (30 -65)$ fb for $M_{T'} = 1\, (1.5)$~TeV respectively with 100 fb$^{-1}$ of integrated luminosity, depending on the branching ratios of the $T'$. Similarly, we find that cross sections of $\sigma_{T'} \sim 27 -60\, (13 - 24)$ fb for $M_{T'} = 1\, (1.5)$ TeV respectively can be excluded with the same amount of data. Our results are minimally model dependent and can be applied to most $T'$ models where $\Gamma_{T'} \ll M_{T'}$.