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Article Citation - WoS: 37Citation - Scopus: 62Measurement of the Bs0 Production Cross Section With Bs0?j/? Decays in Pp Collisions at ?s=7tev(American Physical Society, 2011) Karapınar, Güler; Demir, Durmuş AliThe Bs0 differential production cross section is measured as functions of the transverse momentum and rapidity in pp collisions at √s=7TeV, using the Bs0→J/ψ decay, and compared with predictions based on perturbative QCD calculations at next-to-leading order. The data sample, collected by the CMS experiment at the LHC, corresponds to an integrated luminosity of 40pb -1. The Bs0 is reconstructed from the decays J/ ψ→μ+μ- and →K+K -. The integrated Bs0 cross section times Bs0→J/ψ branching fraction in the range 8<pTB<50GeV/c and |yB|<2.4 is measured to be 6.9±0.6±0.6nb, where the first uncertainty is statistical and the second is systematic. © 2011 CERN.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: 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: 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: 202Citation - Scopus: 214Search for Supersymmetry at the Lhc in Events With Jets and Missing Transverse Energy(American Physical Society, 2011) Karapınar, Güler; Demir, Durmuş AliA search for events with jets and missing transverse energy is performed in a data sample of pp collisions collected at √s=7TeV by the CMS experiment at the LHC. The analyzed data sample corresponds to an integrated luminosity of 1.14fb-1. In this search, a kinematic variable αT is used as the main discriminator between events with genuine and misreconstructed missing transverse energy. No excess of events over the standard model expectation is found. Exclusion limits in the parameter space of the constrained minimal supersymmetric extension of the standard model are set. In this model, squark masses below 1.1 TeV are excluded at 95% C.L. Gluino masses below 1.1 TeV are also ruled out at 95% C.L. for values of the universal scalar mass parameter below 500 GeV. © 2011 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.Article Citation - WoS: 27Citation - Scopus: 38Search for Supersymmetry in Pp Collisions at ?s = 7 Tev in Events With a Single Lepton, Jets, and Missing Transverse Momentum(Springer Verlag, 2011) Karapınar, Güler; Demir, Durmuş AliResults are reported from a search for physics beyond the standard model in proton-proton collisions at a center-of-mass energy of 7 TeV, focusing on the signature with a single, isolated, high-transverse-momentum lepton (electron or muon), energetic jets, and large missing transverse momentum. The data sample comprises an integrated luminosity of 36 pb−1, recorded by the CMS experiment at the LHC. The search is motivated by models of new physics, including supersymmetry. The observed event yields are consistent with standard model backgrounds predicted using control samples obtained from the data. The characteristics of the event sample are consistent with those expected for the production of tt̄ and W + jets events. The results are interpreted in terms of limits on the parameter space for the constrained minimal supersymmetric extension of the standard model.