Projection of searches for pair production of scalar leptoquarks decaying to a top quark and a charged lepton at the HL-LHC

Projections for searches for pair-produced scalar leptoquarks decaying into top quarks and muons or tau leptons for high integrated luminosities of up to $3000\,\mathrm{fb}^{-1}$ at the high luminosity LHC are presented. This study is based on published analysis results of data recorded in the year 2016. It uses scaled signal and background templates to estimate the reach in terms of discovery potential and upper limits on the leptoquark pair production cross section. Two different ways of treating systematic uncertainties are studied. The mass reach for a $5\sigma$ discovery or a $95\%$ confidence level exclusion is expected to increase by 400 to $500\,\mathrm{GeV}$ with respect to the 2016 results. In the case of mixed decays between these two channels, the mass expected to be in reach for a $5\sigma$ discovery and the expected $95\%$ confidence level limit on excluded leptoquark masses ranges from $1200$ to $1700\,\mathrm{GeV}$ and from $1400$ to $1900\,\mathrm{GeV}$ depending on the value of the branching fraction, respectively.