Investigating the Single Production of Vector-Like Quarks Decaying into Top Quark and W Boson through Hadronic Channels at the HL-LHC

Abstract: We investigate the single production of vector-like quarks at the High Luminosity LHC (HL-LHC). With the assumed (enhanced) couplings to third generation quarks of the standard model, vector-like quarks $B/X$ are produced in association with a bottom ($b$) or top ($t$) quark, which correspond to $Bbq$ and $Btq/Xtq$ production modes, including an additional soft forward jet from the spectator quark ($q$). This study focuses on high-mass vector-like quarks $B/X$ decaying into a top quark and a $W$ boson, resulting in the final state jets emerging from hadronically decaying top quark ($t\to Wb$) and $W$ boson ($W\to q\bar{q}'$). The events with $W$ boson and $t$ quark have been analysed using tagging techniques for large-radius jets. The scan ranges of the mass ($1000<m_{B/X}<3000$ GeV) for the relative width $\Gamma_{B/X}/m_{B/X}=0.1$ and $\Gamma_{B/X}/m_{B/X}=0.01$ of vector-like $B/X$ quarks have been investigated. From the results of the analysis, the masses of vector like quarks $B$($X$) up to $2491$ ($2364$) GeV and $2018$ ($1873$) GeV can be excluded corresponding to these relative width cases at $95\%$ CL depending on the type and branching scenarios at integrated luminosity projection of $3$ ab$^{-1}$ at the HL-LHC.