5,257 research outputs found

    Search for the standard model Higgs boson in the \hzzlepjet channel with the CMS experiment at LHC

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    A search for the standard model (SM) Higgs boson decaying into two Z bosons with a subsequent decay into two leptons and two quark jets, H → ZZ → + −q+q−, is presented. The data sample, corresponding to an integrated luminosity of 4.6 fb−1, is collected from proton proton collisions at the centre-of-mass energy of 7 TeV, with the CMS detector at the LHC at CERN, in proton-proton collisions at the centre-of-mass energy of 7 TeV. Discrimination of signal from background events is based on a kinematic selection and exploiting the different angular distribution of signal and background. No evidence for the Higgs boson is found, and upper limits on the Higgs boson production cross section are set between 130 and 600 GeV mass

    Search for a pseudoscalar boson decaying into a ZZ boson and the 125 GeV Higgs boson in ℓ+ℓ−bbˉb\bar{b} final states

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    Results are reported on a search for decays of a pseudoscalar A boson into a ZZ boson and a light scalar h boson, where the Z boson decays into a pair of oppositely-charged electrons or muons, and the h boson decays into bbˉb\bar{b}. The search is based on data from proton–proton collisions at a center-of-mass energy s\sqrt{s}=8 TeV collected with the CMS detector, corresponding to an integrated luminosity of 19.7 fb1fb^{−1} . The h boson is assumed to be the standard model-like Higgs boson with a mass of 125 GeV. With no evidence for signal, upper limits are obtained on the product of the production cross section and the branching fraction of the A boson in the Zh channel. Results are also interpreted in the context of two Higgs doublet models

    Measurement of diffraction dissociation cross sections in pp collisions at s\sqrt{s} = 7 TeV

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    Measurements of diffractive dissociation cross sections in pp collisions at s√=7  TeV are presented in kinematic regions defined by the masses MX and MY of the two final-state hadronic systems separated by the largest rapidity gap in the event. Differential cross sections are measured as a function of ξX=M2X/s in the region −5.53, log10MX>1.1, and log10MY>1.1, a region dominated by DD. The cross sections integrated over these regions are found to be, respectively, 2.99±0.02(stat)+0.32−0.29(syst)  mb, 1.18±0.02(stat)±0.13(syst)  mb, and 0.58±0.01(stat)+0.13−0.11(syst)  mb, and are used to extract extrapolated total SD and DD cross sections. In addition, the inclusive differential cross section, dσ/dΔηF, for events with a pseudorapidity gap adjacent to the edge of the detector, is measured over ΔηF=8.4 units of pseudorapidity. The results are compared to those of other experiments and to theoretical predictions and found compatible with slowly rising diffractive cross sections as a function of center-of-mass energy

    Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

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    A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV