Color sextet scalars at the CERN Large Hadron Collider

Taking a phenomenological approach, we study a color sextet scalar at the LHC. We focus on the QCD production of a color sextet pair ${\ensuremath{\Phi}}_{6}{\overline{\ensuremath{\Phi}}}_{6}$ through $gg$ fusion and $q\overline{q}$ annihilation. Its unique coupling to ${\overline{\ensuremath{\psi}}}^{c}\ensuremath{\psi}$ allows the color sextet scalar to decay into same-sign diquark states, such as ${\ensuremath{\Phi}}_{6}\ensuremath{\rightarrow}tt/t{t}^{*}$. We propose a new reconstruction in the multijet plus same-sign dilepton with missing transverse energy samples ($bb+{\ensuremath{\ell}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\ell}}^{\ifmmode\pm\else\textpm\fi{}}+{\mathrm{E\ensuremath{\llap{\not\;}}}}_{T}+Nj$, $N\ensuremath{\ge}6$) to search for on-shell $tt\overline{t}\overline{t}$ final states from sextet scalar pair production. Thanks to the large QCD production, the search covers the sextet mass range up to 1 TeV for $100\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ integrated luminosity.