WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 175Citation - Scopus: 144Charged Particle Multiplicities in Pp Interactions at ?s = 0.9, 2.36, and 7tev(Springer Verlag, 2011) Karapınar, Güler; Demir, Durmuş AliMeasurements of primary charged hadron multiplicity distributions are presented for non-single-diffractive events in proton-proton collisions at centre-of-mass energies of √s = 0.9, 2.36, and 7TeV, in five pseudorapidity ranges from |η| < 0.5 to |η| < 2.4. The data were collected with the minimum-bias trigger of the CMS experiment during the LHC commissioning runs in 2009 and the 7TeV run in 2010. The multiplicity distribution at √s = 0.9 TeV is in agreement with previous measurements. At higher energies the increase of the mean multiplicity with √s is underestimated by most event generators. The average transverse momentum as a function of the multiplicity is also presented. The measurement of higher-order moments of the multiplicity distribution confirms the violation of Koba-Nielsen-Olesen scaling that has been observed at lower energies.Article Citation - WoS: 17Citation - Scopus: 32Inclusive B-Hadron Production Cross Section With Muons in Pp Collisions at ?s = 7 Tev(Springer Verlag, 2011) Karapınar, Güler; Demir, Durmuş AliA measurement of the b-hadron production cross section in proton-proton collisions at √s = 7TeV is presented. The dataset, corresponding to 85 nb-1, was recorded with the CMS experiment at the LHC using a low-threshold single-muon trigger. Events are selected by the presence of a muon with transverse momentum pμ T > 6GeV with respect to the beam direction and pseudorapidity |ζμ| < 2.1. The transverse momentum of the muon with respect to the closest jet discriminates events containing b hadrons from background. The inclusive b-hadron production cross section is presented as a function of muon transverse momentum and pseudorapidity. The measured total cross section in the kinematic acceptance is σ(pp → b + X → μ + X′) = 1.32 ± 0.01(stat) ± 0.30(syst) ± 0.15(lumi)μb.Article Citation - WoS: 242Citation - Scopus: 228Measurements of Inclusive W and Z Cross Sections in Pp Collisions at ?s = 7 Tev the Cms Collaboration(Springer Verlag, 2011) Karapınar, Güler; Demir, Durmuş AliMeasurements of inclusive W and Z boson production cross sections in pp collisions at √s = 7 TeV are presented, based on 2.9 pb-1 of data recorded by the CMS detector at the LHC. The measurements, performed in the electron and muon decay channels, are combined to give σ(pp → WX) × B(W → l?) = 9.95 ± 0.07 (stat.) ± 0.28 (syst.) ± 1.09 (lumi.) nb and σ(pp → ZX) × B(Z → l +l-) = 0.931 ± 0.026 (stat.) ± 0.023 (syst.) ± 0.102 (lumi.) nb, where l stands for either e or μ. Theoretical predictions, calculated at the next-to-next-to-leading order in QCD using recent parton distribution functions, are in agreement with the measured cross sections. Ratios of cross sections, which incur an experimental systematic uncertainty of less than 4%, are also reported.Article Citation - WoS: 519Citation - Scopus: 401Determination of Jet Energy Calibration and Transverse Momentum Resolution in Cms(IOP Publishing Ltd., 2011) Karapınar, Güler; Demir, Durmuş AliMeasurements of the jet energy calibration and transverse momentum resolution in CMS are presented, performed with a data sample collected in proton-proton collisions at a centre-of-mass energy of 7TeV, corresponding to an integrated luminosity of 36pb-1. The transverse momentum balance in dijet and γ/Z+jets events is used to measure the jet energy response in the CMS detector, as well as the transverse momentum resolution. The results are presented for three different methods to reconstruct jets: a calorimeter-based approach, the "Jet-Plus-Track" approach, which improves the measurement of calorimeter jets by exploiting the associated tracks, and the "Particle Flow" approach, which attempts to reconstruct individually each particle in the event, prior to the jet clustering, based on information from all relevant subdetectors.Article Citation - WoS: 48Citation - Scopus: 55Search for Bs0??+?- and B0??+?- Decays in Pp Collisions at ?s=7tev(American Physical Society, 2011) Karapınar, Güler; Demir, Durmuş AliA search for the rare decays Bs0→μ+μ- and B0→μ+μ- is performed in pp collisions at √s=7TeV, with a data sample corresponding to an integrated luminosity of 1.14fb-1, collected by the CMS experiment at the LHC. In both cases, the number of events observed after all selection requirements is consistent with expectations from background and standard-model signal predictions. The resulting upper limits on the branching fractions are B(Bs0→μ +μ-)<1.9×10-8 and B(B0→μ+μ-)<4.6×10-9, at 95% confidence level. © 2011 CERN.Article Citation - WoS: 51Citation - Scopus: 58Search for New Physics With a Monojet and Missing Transverse Energy in Pp Collisions at ?s=7tev(American Physical Society, 2011) Karapınar, Güler; Demir, Durmuş AliA study of events with missing transverse energy and an energetic jet is performed using pp collision data at a center-of-mass energy of 7 TeV. The data were collected by the CMS detector at the LHC, and correspond to an integrated luminosity of 36pb-1. An excess of these events over standard model contributions is a signature of new physics such as large extra dimensions and unparticles. The number of observed events is in good agreement with the prediction of the standard model, and significant extension of the current limits on parameters of new physics benchmark models is achieved. © 2011 CERN.Article Citation - WoS: 61Citation - Scopus: 71Measurement of the Tt¯ Production Cross Section in Pp Collisions at 7 Tev in Lepton+jets Events Using B-Quark Jet Identification(American Physical Society, 2011) Karapınar, Güler; Demir, Durmuş AliA new measurement of the inclusive production cross section for pp→tt̄ is performed at a center-of-mass energy of 7 TeV using data collected by the CMS experiment at the LHC. The analysis uses a data sample corresponding to an integrated luminosity of 36pb-1, and is based on the final state with one isolated, high transverse momentum muon or electron, missing transverse energy, and hadronic jets. The tt̄ content of the selected events is enhanced by requiring the presence of at least one jet consistent with b-quark hadronization. The measured cross section is 150±9(stat)±17(syst)±6(lumi)pb and is in agreement with higher-order QCD calculations. The combination of this measurement with a previous CMS result based on dileptons gives 154±17(stat+syst) ±6(lumi)pb. © 2011 CERN.Article Citation - WoS: 52Citation - Scopus: 47Measurement of the Drell-Yan Cross Section in Pp Collisions at ? S = 7 Tev(Springer Verlag, 2011) Karapınar, Güler; Demir, Durmuş AliThe Drell-Yan differential cross section is measured in pp collisions at √ s = 7TeV, from a data sample collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 36 pb-1. The cross section measurement, normalized to the measured cross section in the Z region, is reported for both the dimuon and dielectron channels in the dilepton invariant mass range 15{600 GeV. The normalized cross section values are quoted both in the full phase space and within the detector acceptance. The effect of final state radiation is also identified. The results are found to agree with theoretical predictions. Copyright CERN.Article Citation - WoS: 255Citation - Scopus: 228Measurement of the Inclusive W and Z Production Cross Sections in Pp Collisions at ?s = 7 Tev With the Cms Experiment(Springer Verlag, 2011) Karapınar, Güler; Demir, Durmuş AliA measurement of inclusive W and Z production cross sections in pp collisions at √s = 7TeV is presented. The electron and muon decay channels are analyzed in a data sample collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 pb-1. The measured inclusive cross sections are σ(pp → WX) × ß(W → lν) = 10.31 × 0.02 (stat.) × 0.09 (syst.) × 0.10 (th.) × 0.41 (lumi.) nb and σ(pp → ZX) x B(Z → l +l- = 0.974 × 0.007 (stat.) × 0.007 (syst.) × 0.018 (th.) × 0.039 (lumi.) nb, limited to the dilepton invariant mass range 60 to 120 GeV. The luminosity-independent cross section ratios are (σ(pp → WX) × B(W → lv))/(σ(pp → ZX) × B(Z → l+l-)) = 10.54 × 0.07 (stat.) × 0.08 (syst.) × 0.16 (th.) and (σ(pp → W+X) × B(W+ → l+ν))/(σ(pp → W-X) × B(W- → l-v̄)) = 1.421×0.006 (stat.) ×0.014 (syst.) ×0.029 (th.). The measured values agree with next-to-next-to-leading order QCD cross section calculations based on recent parton distribution functions. Copyright CERN.Article Citation - WoS: 26Citation - Scopus: 29Search for Light Resonances Decaying Into Pairs of Muons as a Signal of New Physics(Springer Verlag, 2011) Karapınar, Güler; Demir, Durmuş AliA search for groups of collimated muons is performed using a data sample collected by the CMS experiment at the LHC, at a centre-of-mass energy of 7 TeV, and corresponding to an integrated luminosity of 35 pb-1. The analysis searches for production of new low-mass states decaying into pairs of muons and is designed to achieve high sensitivity to a broad range of models predicting leptonic jet signatures. With no excess observed over the background expectation, upper limits on the production cross section times branching fraction times acceptance are set, ranging from 0.1 to 0.5 pb at the 95% CL depending on event topology. In addition, the results are interpreted in several benchmark models in the context of supersymmetry with a new light dark sector exploring previously inaccessible parameter space.