Search for Contact Interactions in Dilepton Mass Spectra in pp Collisions at sqrt(s) = 8 TeV

A search for contact interactions in events with muon or electron pairs has been performed. The data samples were collected by the CMS detector and correspond to integrated luminosities of 20.6 and 19.7\,fb$^{-1}$ for the muon and electron channels, respectively, for proton-proton collisions at $\sqrt{s}=8$\,TeV. Within the context of a quark and lepton compositeness model with a left-left isoscalar contact interaction, 95\% CL lower limits are set on $\Lambda$, the energy scale parameter for the contact interaction. For dimuons the limits are 12.0 and 15.2\,TeV for destructive and constructive interference with Drell--Yan production, respectively; for dielectrons the limits are 13.5 and 18.3\,TeV. These limits are the most stringent to date.