Results are reported from a search for the pair production of top squarks, the supersymmetric partners of top quarks, in final states with jets and missing transverse momentum. The data sample used in this search was collected by the CMS detector and corresponds to an integrated luminosity of 18.9fb-1fb-1 of proton-proton collisions at a centre-of-mass energy of 8TeVTeVproduced by the LHC. The search features novel background suppression and prediction methods, including a dedicated top quark pair reconstruction algorithm. The data are found to be in agreement with the predicted backgrounds. Exclusion limits are set in simplified supersymmetry models with the top squark decaying to jets and an undetected neutralino, either through a top quark or through a bottom quark and chargino. Models with the top squark decaying via a top quark are excluded for top squark masses up to 755GeVGeV in the case of neutralino masses below 200GeVGeV. For decays via a chargino, top squark masses up to 620GeVGeV are excluded, depending on the masses of the chargino and neutralino.
A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (HH) in proton-proton collisions collected by the CMS experiment at the LHC at s√=8TeVs=8TeV. The data correspond to an integrated luminosity of 19.7fb−1fb−1. The search considers HHHH resonances with masses between 1 and 3TeVTeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and tt¯tt¯ events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 % confidence level for the product of the production cross section and branching fraction σ(gg→X)B(X→HH→bb¯¯¯bb¯¯¯)σ(gg→X)B(X→HH→bb¯bb¯) range from 10 to 1.5\,fb\,fb for the mass of X from 1.15 to 2.0TeVTeV, significantly extending previous searches. For a warped extra dimension theory with a mass scale ΛR=1ΛR=1TeVTeV, the data exclude radion scalar masses between 1.15 and 1.55TeVTeV.
A search for narrow resonances decaying to an electron and a muon is presented. The eeμμ mass spectrum is also investigated for non-resonant contributions from the production of quantum black holes (QBHs).