Studies of Sensitivity to New Dilepton and Ditop Resonances with an Upgraded ATLAS Detector at a High-Luminosity LHC

The Phase 2 upgrade of the LHC and the ATLAS detector will increase the sensitivity to high-mass resonances beyond the Standard Model. The expected gain in sensitivity if the ATLAS dataset of $pp$ collisions were increased from $300\,\mathrm{fb}^{-1}$ to $1000\,\mathrm{fb}^{-1}$ and $3000\,\mathrm{fb}^{-1}$ at a center-of-mass energy of $14\,\mathrm{TeV}$ is estimated using parameterizations of detector performance. The increase of a factor of ten in integrated luminosity raises the sensitivity to high-mass resonances by up to 2.4 TeV. With $3000\,\mathrm{fb}^{-1}$ of data, $t\bar{t}$ and dilepton resonances with masses up to 6.7 and 7.8 TeV, respectively, can be probed.