4,244 research outputs found

    Latest results on differential cross sections as a function of kinematic variables at the LHC and Tevatron

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    An overview of recent measurements of differential top quark pair (ttˉt\bar{t}) production cross sections is presented, including results in boosted topologies and results both at parton and particle level. The first measurements of differential single top quark t-channel production cross sections in proton-proton collisions are as well presented. The results are obtained using data collected with the ATLAS and CMS experiments in proton-proton collisions at centre-of-mass energies of 7 TeV and 8 TeV. References to the latest results by the Tevatron experiments are also given. The data are compared with several predictions from perturbative QCD calculations up to approximate next-to-next-to-leading-order precision (approx. NNLO).Comment: 5 pages, 4 figures, TOP2014 Conferenc

    ttˉ{\rm t\bar{t}} cross section measurements in CMS

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    An overview of the most recent measurements of inclusive top quark pair production cross section is presented. The results are obtained using data collected with the CMS experiment in proton-proton collisions at centre-of-mass energies of 5.02, 7, 8 and 13 TeV. The data are compared with the predictions from perturbative QCD calculations at full NNLO+NNLL accuracy.Comment: 6 pages, 5 figures, TOP2016 conferenc

    La participación laboral de las mujeres: un reto para el bienestar social.

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    Este trabajo ha sido posible gracias a la cobertura de los proyectos de investigación “Riesgos y oportunidades a lo largo del curso de la vida en las sociedades postindustriales” (CICYT. Sec2003-06799), dirigido por Esping-Andersen (Universitat Pompeu Fabra) y “Nuevos Riesgos Sociales y Trayectorias de las Políticas del Bienestar” (NURSOPOB) (MEC, Plan Nacional de I+D+I), dirigidos por Luis Moreno (Unidad de Políticas Comparadas, CSIC). Agradezco a ambos el apoyo que me han prestado para poderle llevar a cabo, y de forma muy particular, a Ana Arriba y Luis Moreno, por sus comentarios y colaboración en versiones anteriores del mismo

    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

    Combined search for the quarks of a sequential fourth generation

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    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

    Search for New Physics with Jets and Missing Transverse Momentum in pp collisions at sqrt(s) = 7 TeV

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    A search for new physics is presented based on an event signature of at least three jets accompanied by large missing transverse momentum, using a data sample corresponding to an integrated luminosity of 36 inverse picobarns collected in proton--proton collisions at sqrt(s)=7 TeV with the CMS detector at the LHC. No excess of events is observed above the expected standard model backgrounds, which are all estimated from the data. Exclusion limits are presented for the constrained minimal supersymmetric extension of the standard model. Cross section limits are also presented using simplified models with new particles decaying to an undetected particle and one or two jets
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