The performance of muon reconstruction in CMS is evaluated using a large data sample of cosmic-ray muons recorded in 2008. Efficiencies of various high-level trigger, identification, and ...reconstruction algorithms have been measured for a broad range of muon momenta, and were found to be in good agreement with expectations from Monte Carlo simulation. The relative momentum resolution for muons crossing the barrel part of the detector is better than 1% at 10 GeV/c and is about 8% at 500 GeV/c, the latter being only a factor of two worse than expected with ideal alignment conditions. Muon charge misassignment ranges from less than 0.01% at 10 GeV/c to about 1% at 500 GeV/c.
The production cross section of a W boson in association with two b jets is measured using a sample of proton-proton collisions at Formula: see text collected by the CMS experiment at the CERN LHC. ...The data sample corresponds to an integrated luminosity of 19.8Formula: see text. The W bosons are reconstructed via their leptonic decays, Formula: see text, where Formula: see text or Formula: see text. The fiducial region studied contains exactly one lepton with transverse momentum Formula: see text and pseudorapidity Formula: see text, with exactly two b jets with Formula: see text and Formula: see text and no other jets with Formula: see text and Formula: see text. The cross section is measured to be Formula: see text+Formula: see text, in agreement with standard model predictions.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A measurement of the top quark pair production (Formula: see text) cross section in proton-proton collisions at the centre-of-mass energy of 8Formula: see text is presented using data collected with ...the CMS detector at the LHC, corresponding to an integrated luminosity of 19.6Formula: see text. This analysis is performed in the Formula: see text decay channels with one isolated, high transverse momentum electron or muon and at least four jets, at least one of which is required to be identified as originating from hadronization of a b quark. The calibration of the jet energy scale and the efficiency of b jet identification are determined from data. The measured Formula: see text cross section is Formula: see text. This measurement is compared with an analysis of 7Formula: see text data, corresponding to an integrated luminosity of 5.0Formula: see text, to determine the ratio of 8Formula: see text to 7Formula: see text cross sections, which is found to be Formula: see text. The measurements are in agreement with QCD predictions up to next-to-next-to-leading order.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A search for new phenomena is performed in final states containing one or more jets and an imbalance in transverse momentum in pp collisions at a centre-of-mass energy of 13Formula: see text. The ...analysed data sample, recorded with the CMS detector at the CERN LHC, corresponds to an integrated luminosity of 2.3Formula: see text. Several kinematic variables are employed to suppress the dominant background, multijet production, as well as to discriminate between other standard model and new physics processes. The search provides sensitivity to a broad range of new-physics models that yield a stable weakly interacting massive particle. The number of observed candidate events is found to agree with the expected contributions from standard model processes, and the result is interpreted in the mass parameter space of fourteen simplified supersymmetric models that assume the pair production of gluinos or squarks and a range of decay modes. For models that assume gluino pair production, masses up to 1575 and 975Formula: see text are excluded for gluinos and neutralinos, respectively. For models involving the pair production of top squarks and compressed mass spectra, top squark masses up to 400Formula: see text are excluded.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A search for heavy resonances with masses above 1
, decaying to final states containing a vector boson and a Higgs boson, is presented. The search considers hadronic decays of the vector boson, and ...Higgs boson decays to b quarks. The decay products are highly boosted, and each collimated pair of quarks is reconstructed as a single, massive jet. The analysis is performed using a data sample collected in 2016 by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13
, corresponding to an integrated luminosity of 35.9
. The data are consistent with the background expectation and are used to place limits on the parameters of a theoretical model with a heavy vector triplet. In the benchmark scenario with mass-degenerate
and
bosons decaying predominantly to pairs of standard model bosons, for the first time heavy resonances for masses as high as 3.3
are excluded at 95% confidence level, setting the most stringent constraints to date on such states decaying into a vector boson and a Higgs boson.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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
, and a center-of-mass energy of 13
. 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
for gluinos, 830
for bottom squarks. The excluded mass range for heavy (pseudo)scalar bosons is 350-360 (350-410)
. Additionally, model-independent limits in several topological regions are provided, allowing for further interpretations of the results.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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