71 research outputs found

    Measurement of WZ and ZZ production in pp collisions at sqrt{s}=8TeV in final states with b-tagged jets

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    Measurements are reported of the WZ and ZZ production cross sections in proton-proton collisions at in final states where one Z boson decays to b-tagged jets. The other gauge boson, either W or Z, is detected through its leptonic decay (either , or , , or ). The results are based on data corresponding to an integrated luminosity of 18.9 fb collected with the CMS detector at the Large Hadron Collider. The measured cross sections, and , are consistent with next-to-leading order quantum chromodynamics calculations

    Measurements of b-jet nuclear modification factors in pPb and PbPb collisions with CMS

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    Measurement of the Zγ production cross section in pp collisions at 8 TeV and search for anomalous triple gauge boson couplings

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    Open Access, Copyright CERN, for the benefit of the CMS Collaboration. Article funded by SCOAP3.Abstract: The cross section for the production of Zγ in proton-proton collisions at 8 TeV is measured based on data collected by the CMS experiment at the LHC corresponding to an integrated luminosity of 19.5 fb−1. Events with an oppositely-charged pair of muons or electrons together with an isolated photon are selected. The differential cross section as a function of the photon transverse momentum is measured inclusively and exclusively, where the exclusive selection applies a veto on central jets. The observed cross sections are compatible with the expectations of next-to-next-to-leading-order quantum chromodynamics. Limits on anomalous triple gauge couplings of ZZγ and Zγγ are set that improve on previous experimental results obtained with the charged lepton decay modes of the Z boson

    Searches for new physics using the t(t)over-bar invariant mass distribution in pp collisions at √s=8 TeV

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    This is the pre-print version of the final published paper that is available from the link belowSearches for anomalous top quark-antiquark production are presented, based on pp collisions at √s=8  TeV . The data, corresponding to an integrated luminosity of 19:7 fb^-1, were collected with the CMS detector at the LHC. The observed tt invariant mass spectrum is found to be compatible with the standard model prediction. Limits on the production cross section times branching fraction probe, for the first time, a region of parameter space for certain models of new physics not yet constrained by precision measurements

    Search for physics beyond the standard model in events with two leptons of same sign, missing transverse momentum, and jets in proton-proton collisions at root s=13TeV

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    A data sample of events from proton–proton collisions with two isolated same-sign leptons, missing transverse momentum, and jets is studied in a search for signatures of new physics phenomena by the CMS Collaboration at the LHC. The data correspond to an integrated luminosity of 35.9 fb−1, and a center-of-mass energy of 13 TeV. The properties of the events are consistent with expectations from standard model processes, and no excess yield is observed. Exclusion limits at 95% confidence level are set on cross sections for the pair production of gluinos, squarks, and same-sign top quarks, as well as top-quark associated production of a heavy scalar or pseudoscalar boson decaying to top quarks, and on the standard model production of events with four top quarks. The observed lower mass limits are as high as 1500 GeV for gluinos, 830 GeV for bottom squarks. The excluded mass range for heavy (pseudo)scalar bosons is 350–360 (350–410) GeV. Additionally, model-independent limits in several topological regions are provided, allowing for further interpretations of the results
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