Search for contact interactions and large extra dimensions in the dilepton channel using proton-proton collisions at sqrt(s) = 8 TeV with the ATLAS detector

A search is conducted for non-resonant new phenomena in dielectron and dimuon final states, originating 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 sqrt(s) = 8 TeV. The dilepton invariant mass spectrum is a discriminating variable in both searches, with the contact interaction search additionally utilizing the dilepton forward-backward asymmetry. No significant deviations from the Standard Model expectation are observed. Lower limits are set on the new physics parameters of interest at the 95% credibility level. For ℓℓqq contact interactions, lower limits are set on the contact interaction scale Λ between 15.4 TeV and 26.3 TeV. Lower limits are also set on the string scale MS for large extra spatial dimensions, from 4.1 TeV to 6.1 TeV.