Search for new high-mass phenomena in the dilepton final state using 36.1 fb$^{-1}$ of proton-proton collision data at $\sqrt{s} =$ 13 TeV with the ATLAS detector

A search is conducted for new resonant and non-resonant high-mass phenomena in dielectron and dimuon final states. The search uses 36.1 fb$^{-1}$ of proton-proton collision data, collected at $\sqrt{s}$ = 13 TeV by the ATLAS experiment at the LHC in 2015 and 2016. The dilepton invariant mass is used as the discriminating variable. No significant deviation from the Standard Model prediction is observed. Upper limits at 95% credibility level are set on the cross-section times branching ratio for resonances decaying to dileptons, which are converted into lower limits on the resonance mass, up to 4.1 TeV for the E6-motivated Z'$_{\chi}$. Lower limits on the $\ell\ell qq$ contact interaction scale are set between 23.5 TeV and 40.1 TeV, depending on the model.