Combined search for the quarks of a sequential fourth generation

Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO

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Search for massive resonances in dijet systems containing jets tagged as W or Z boson decays in pp collisions at √s=8 TeV

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Search for physics beyond the standard model in dilepton mass spectra in proton-proton collisions at √s=8 TeV

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Searches for supersymmetry using the M-T2 variable in hadronic events produced in pp collisions at 8 TeV

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Constraints on parton distribution functions and extraction of the strong coupling constant from the inclusive jet cross section in pp collisions at √s=7 TeV

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Measurement of the mass difference between top quark and antiquark in pp collisions at root s=8 TeV

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Measurement of the W+W− cross section in pp collisions at s√=7 TeV and limits on anomalous WWγ and WWZ couplings

A measurement of W+W− production in pp collisions at s√=7 TeV is presented. The data were collected with the CMS detector at the LHC, and correspond to an integrated luminosity of 4.92±0.11 fb−1. The W+W− candidates consist of two oppositely charged leptons, electrons or muons, accompanied by large missing transverse energy. The W+W− production cross section is measured to be 52.4±2.0 (stat.)±4.5 (syst.)±1.2 (lum.) pb. This measurement is consistent with the standard model prediction of 47.0±2.0 pb at next-to-leading order. Stringent limits on the WWγ and WWZ anomalous triple gauge-boson couplings are set