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Permanent URI for this collectionhttps://hdl.handle.net/11147/6849
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Article Citation - WoS: 153Study of the Inclusive Production of Charged Pions, Kaons, and Protons in Pp Collisions at ?s=0.9, 2.76, and 7 Tev(Springer Verlag, 2012) Karapınar, Güler; CMS CollaborationSpectra of identified charged hadrons are measured in pp collisions at the LHC for root s = 0.9, 2.76, and 7 TeV. Charged pions, kaons, and protons in the transverse-momentum range p(T) approximate to 0.1-1.7 GeV/c and for rapidities vertical bar y vertical bar < 1 are identified via their energy loss in the CMS silicon tracker. The average p(T) increases rapidly with the mass of the hadron and the event charged-particle multiplicity, independently of the center-of-mass energy. The fully corrected p(T) spectra and integrated yields are compared to various tunes of the PYTHIA 6 and PYTHIA 8 event generators.Article Citation - WoS: 43Measurement of the Top-Quark Mass in T(t)over-Bar Events With Dilepton Final States in Pp Collisions at ?s=7 Tev(Springer Verlag, 2012) Karapınar, Güler; CMS CollaborationThe top-quark mass is measured in proton-proton collisions at root s = 7 TeV using a data sample corresponding to an integrated luminosity of 5.0 fb(-1) collected by the CMS experiment at the LHC. The measurement is performed in the dilepton decay channel t (t) over bar -> (l(+)nu(l)b) (l-(nu) over bar (l)(b) over bar), where l = e, mu. Candidate top-quark decays are selected by requiring two leptons, at least two jets, and imbalance in transverse momentum. The mass is reconstructed with an analytical matrix weighting technique using distributions derived from simulated samples. Using a maximum-likelihood fit, the top-quark mass is determined to be 172.5 +/- 0.4 (stat.) +/- 1.5 (syst.) GeV.Article Citation - WoS: 62Measurement of the Sum of Ww and Wz Production With W Plus Dijet Events in Pp Collisions at ?s=7 Tev(Springer Verlag, 2013) Karapınar, Güler; CMS CollaborationA measurement of the inclusive WW+WZ diboson production cross section in proton-proton collisions is reported, based on events containing a leptonically decaying W boson and exactly two jets. The data sample, collected at root s = 7 TeV with the CMS detector at the LHC, corresponds to an integrated luminosity of 5.0 fb(-1). The measured value of the sum of the inclusive WW and WZ cross sections is sigma(pp -> WW + WZ) = 68.9 +/- 8.7 (stat.) +/- 9.7 (syst.) +/- 1.5 (lum.) pb, consistent with the standard model prediction of 65.6 +/- 2.2 pb. This is the first measurement of WW+WZ production in pp collisions using this signature. No evidence for anomalous triple gauge couplings is found and upper limits are set on their magnitudes.Article Citation - WoS: 131Measurement of Differential Top-Quark Production Cross Sections in Pp Collisions at ?s=7 Tev(Springer Verlag, 2013) Karapınar, Güler; CMS CollaborationNormalised differential top-quark-pair production cross sections are measured in pp collisions at a centre-of-mass energy of 7 TeV at the LHC with the CMS detector using data recorded in 2011 corresponding to an integrated luminosity of 5.0 fb(-1). The measurements are performed in the lepton + jets decay channels (e + jets and mu + jets) and the dilepton decay channels (e(+)e(-), mu(+)mu(-), and mu(+/-)e(-/+)). The t (t) over bar differential cross section is measured as a function of kinematic properties of the final-state charged leptons and jets associated to b quarks, as well as those of the top quarks and the t (t) over bar system. The data are compared with several predictions from perturbative QCD calculations up to approximate next-to-next-to-leading-order precision. No significant deviations from the standard model are observed.Article Citation - WoS: 4Search for New Physics in Final States With a Lepton and Missing Transverse Energy in Pp Collisions at the Lhc(American Physical Society, 2013) CMS Collaboration; Karapınar, GülerThis Letter describes the search for an enhanced production rate of events with a charged lepton and a neutrino in high-energy pp collisions at the LHC. The analysis uses data collected with the CMS detector, with an integrated luminosity of 5.0 fb(-1) at root s = 7 TeV, and a further 3.7 fb(-1) at root s = 8 TeV. No evidence is found for an excess. The results are interpreted in terms of limits on a heavy charged gauge boson (W') in the sequential standard model, a split universal extra dimension model, and contact interactions in the helicity-nonconserving model. For the last, values of the binding energy below 10.5 (8.8) TeV in the electron (muon) channel are excluded at a 95% confidence level. Interpreting the l(nu) final state in terms of a heavy W' with standard model couplings, masses below 2.90 TeV are excluded. DOI: 10.1103/PhysRevD.87.072005Article Citation - WoS: 72Search for a Standard-Model Higgs Boson With a Mass in the Range 145 To 1000 Gev at the Lhc(Springer Verlag, 2013) Karapınar, Güler; CMS CollaborationA search for a standard-model-like Higgs boson in the H -> WW and H -> ZZ decay channels is reported, for Higgs boson masses in the range 145 < m(H) < 1000 GeV. The search is based upon proton-proton collision data samples corresponding to an integrated luminosity of up to 5.1 fb(-1) at root s = 7 TeV and up to 5.3 fb(-1) at root s = 8 TeV, recorded by the CMS experiment at the LHC. The combined upper limits at 95 % confidence level on products of the cross section and branching fractions exclude a standard-model-like Higgs boson in the range 145 < m(H) < 710 GeV, thus extending the mass region excluded by CMS from 127-600 GeV up to 710 GeV.Article Citation - WoS: 11Search for Physics Beyond the Standard Model in Events With Tau Leptons, Jets, and Large Transverse Momentum Imbalance in Pp Collisions at ?s=7 Tev(Springer Verlag, 2013) Karapınar, Güler; CMS CollaborationA search for physics beyond the standard model is performed with events having one or more hadronically decaying tau leptons, highly energetic jets, and large transverse momentum imbalance. The data sample corresponds to an integrated luminosity of 4.98 fb(-1) of proton-proton collisions at root s = 7 TeV collected with the CMS detector at the LHC in 2011. The number of observed events is consistent with predictions for standard model processes. Lower limits on the mass of the gluino in supersymmetric models are determined.Article Citation - WoS: 130Search for Supersymmetry in Hadronic Final States With Missing Transverse Energy Using the Variables Alpha(t) and B-Quark Multiplicity in Pp Collisions at ?s=8 Tev(Springer Verlag, 2013) Karapınar, Güler; CMS CollaborationAn inclusive search for supersymmetric processes that produce final states with jets and missing transverse energy is performed in pp collisions at a centre-of-mass energy of 8 TeV. The data sample corresponds to an integrated luminosity of 11.7 fb(-1) collected by the CMS experiment at the LHC. In this search, a dimensionless kinematic variable, alpha(T), is used to discriminate between events with genuine and misreconstructed missing transverse energy. The search is based on an examination of the number of reconstructed jets per event, the scalar sum of transverse energies of these jets, and the number of these jets identified as originating from bottom quarks. No significant excess of events over the standard model expectation is found. Exclusion limits are set in the parameter space of simplified models, with a special emphasis on both compressed-spectrum scenarios and direct or gluino-induced production of third-generation squarks. For the case of gluino-mediated squark production, gluino masses up to 950-1125 GeV are excluded depending on the assumed model. For the direct pair-production of squarks, masses up to 450 GeV are excluded for a single light first-or second-generation squark, increasing to 600 GeV for bottom squarks.Article Citation - WoS: 9Measurement of Neutral Strange Particle Production in the Underlying Event in Proton-Proton Collisions at Root S=7 Tev(American Physical Society, 2013) CMS Collaboration; Karapınar, GülerMeasurements are presented of the production of primary K-S(0) and Lambda particles in proton-proton collisions at root s = 7 TeV in the region transverse to the leading charged-particle jet in each event. The average multiplicity and average scalar transverse momentum sum of K-S(0) and Lambda particles measured at pseudorapidities vertical bar eta vertical bar < 2 rise with increasing charged-particle jet p(T) in the range 1-10 GeV/c and saturate in the region 10-50 GeV/c. The rise and saturation of the strange-particle yields and transverse momentum sums in the underlying event are similar to those observed for inclusive charged particles, which confirms the impact-parameter picture of multiple parton interactions. The results are compared to recent tunes of the PYTHIA Monte Carlo event generator. The PYTHIA simulations underestimate the data by 15%-30% for K-S(0) mesons and by about 50% for Lambda baryons, a deficit similar to that observed for the inclusive strange-particle production in non-single-diffractive proton-proton collisions. The constant strange-to charged-particle activity ratios with respect to the leading jet p(T) and similar trends for mesons and baryons indicate that the multiparton-interaction dynamics is decoupled from parton hadronization, which occurs at a later stage.Article Citation - WoS: 98Measurement of the W+w- Cross Section in Pp Collisions at and Limits on Anomalous Ww Gamma and Wwz Couplings(Springer Verlag, 2013) Karapınar, Güler; CMS CollaborationA measurement of W+W- production in pp collisions at is presented. The data were collected with the CMS detector at the LHC, and correspond to an integrated luminosity of 4.92 +/- 0.11 fb(-1). The W+W- candidates consist of two oppositely charged leptons, electrons or muons, accompanied by large missing transverse energy. The W+W- production cross section is measured to be 52.4 +/- 2.0 (stat.)+/- 4.5 (syst.)+/- 1.2 (lum.) pb. This measurement is consistent with the standard model prediction of 47.0 +/- 2.0 pb at next-to-leading order. Stringent limits on the WW gamma and WWZ anomalous triple gauge-boson couplings are set.