Search for contact interactions and large extra dimensions in the dilepton channel using proton–proton collisions at $$\sqrt{s}~=$$ s = 8 TeV with the ATLAS detector

A search is conducted for non-resonant new phenomena in dielectron and dimuon final states, originat- ing from either contact interactions or large extra spatial dimensions. The LHC 2012 proton–proton collision dataset recorded by the ATLAS detector is used, corresponding to 20 fb−1 at √s = 8 TeV. The dilepton invariant mass spec- trum is a discriminating variable in both searches, with the contact interaction search additionally utilizing the dilep- ton forward-backward asymmetry. No significant deviations from the Standard Model expectation are observed. Lower limits are set on the llq q contact interaction scale between 15.4 TeV and 26.3 TeV , at the 95 % credibility level. For large extra spatial dimensions, lower limits are set on the string scale MS between 3.2 TeV to 5.0 TeV.