Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 40Citation - Scopus: 46Measurement of the Associated Production of a Single Top Quark and a Z Boson in Pp Collisions At, Root S=13 Tev(Elsevier Ltd., 2018) Karapınar, Güler; CMS CollaborationA measurement is presented of the associated production of a single top quark and a Z boson. The study uses data from proton-proton collisions at, root s = 13 TeV recorded by the CMS experiment, corresponding to an integrated luminosity of 35.9 fb(-1). Using final states with three leptons (electrons or muons), the tZq production cross section is measured to be sigma (pp -> tZq -> Wbl(+)l(-)q) = 123(-31)(+33)(stat)(-23)(+29)(syst) fb, where l stands for electrons, muons, or tau leptons, with observed and expected significances of 3.7 and 3.1 standard deviations, respectively. C) 2018 The Author. Published by Elsevier B.V.Article Citation - WoS: 30Citation - Scopus: 30Search for a Heavy Resonance Decaying Into a Z Boson and a Vector Boson in the ??¯qq¯ Final State(Springer Verlag, 2018) CMS Collaboration; Karapınar, GülerA search is presented for a heavy resonance decaying into either a pair of Z bosons or a Z boson and a W boson (ZZ or WZ), with a Z boson decaying into a pair of neutrinos and the other boson decaying hadronically into two collimated quarks that are reconstructed as a highly energetic large-cone jet. The search is performed using the data collected with the CMS detector at the CERN LHC during 2016 in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to a total integrated luminosity of 35.9 fb−1. No excess is observed in data with regard to background expectations. Results are interpreted in scenarios of physics beyond the standard model. Limits at 95% confidence level on production cross sections are set at 0.9 fb (63 fb) for spin-1 W′ bosons, included in the heavy vector triplet model, with mass 4.0 TeV (1.0 TeV), and at 0.5 fb (40 fb) for spin-2 bulk gravitons with mass 4.0 TeV (1.0 TeV). Lower limits are set on the masses of W′ bosons in the context of two versions of the heavy vector triplet model of 3.1TeV and 3.4 TeV, respectively.Article Citation - WoS: 11Citation - Scopus: 23Search for Physics Beyond the Standard Model in Events With High-Momentum Higgs Bosons and Missing Transverse Momentum in Proton-Proton Collisions at 13 Tev(American Physical Society, 2018) CMS Collaboration; Karapınar, GülerA search for physics beyond the standard model in events with one or more high-momentum Higgs bosons, H, decaying to pairs of b quarks in association with missing transverse momentum is presented. The data, corresponding to an integrated luminosity of 35.9 fb-1, were collected with the CMS detector at the LHC in proton-proton collisions at the center-of-mass energy s=13 TeV. The analysis utilizes a new b quark tagging technique based on jet substructure to identify jets from H→bb. Events are categorized by the multiplicity of H-tagged jets, jet mass, and the missing transverse momentum. No significant deviation from standard model expectations is observed. In the context of supersymmetry (SUSY), limits on the cross sections of pair-produced gluinos are set, assuming that gluinos decay to quark pairs, H (or Z), and the lightest SUSY particle, LSP, through an intermediate next-to-lightest SUSY particle, NLSP. With large mass splitting between the NLSP and LSP, and 100% NLSP branching fraction to H, the lower limit on the gluino mass is found to be 2010 GeV.Article Citation - WoS: 92Citation - Scopus: 211Search for Heavy Neutral Leptons in Events With Three Charged Leptons in Proton-Proton Collisions at ?s = 13 Tev(American Physical Society, 2018) CMS Collaboration; Karapınar, GülerA search for a heavy neutral lepton N of Majorana nature decaying into a W boson and a charged lepton is performed using the CMS detector at the LHC. The targeted signature consists of three prompt charged leptons in any flavor combination of electrons and muons. The data were collected in proton-proton collisions at a center-of-mass energy of 13 TeV, with an integrated luminosity of 35.9 fb-1. The search is performed in the N mass range between 1 GeV and 1.2 TeV. The data are found to be consistent with the expected standard model background. Upper limits are set on the values of |VeN|2 and |VμN|2, where V N is the matrix element describing the mixing of N with the standard model neutrino of flavor. These are the first direct limits for N masses above 500 GeV and the first limits obtained at a hadron collider for N masses below 40 GeV.Article Citation - WoS: 82Citation - Scopus: 100Evidence for the Higgs Boson Decay To a Bottom Quark–antiquark Pair(Elsevier Ltd., 2018) CMS Collaboration; Karapınar, GülerA search for the standard model (SM) Higgs boson (H) decaying to bb‾ when produced in association with an electroweak vector boson is reported for the following processes: Z(νν)H, W(μν)H, W(eν)H, Z(μμ)H, and Z(ee)H. The search is performed in data samples corresponding to an integrated luminosity of 35.9fb−1 at s=13TeV recorded by the CMS experiment at the LHC during Run 2 in 2016. An excess of events is observed in data compared to the expectation in the absence of a H→bb‾ signal. The significance of this excess is 3.3 standard deviations, where the expectation from SM Higgs boson production is 2.8. The signal strength corresponding to this excess, relative to that of the SM Higgs boson production, is 1.2±0.4. When combined with the Run 1 measurement of the same processes, the signal significance is 3.8 standard deviations with 3.8 expected. The corresponding signal strength, relative to that of the SM Higgs boson, is 1.06−0.29 +0.31.Article Citation - WoS: 29Citation - Scopus: 55Search for a Heavy Right-Handed W Boson and a Heavy Neutrino in Events With Two Same-Flavor Leptons and Two Jets at ?s=13 Tev(Springer Verlag, 2018) CMS Collaboration; Karapınar, GülerA search for a heavy right-handed W boson (WR) decaying to a heavy right-handed neutrino and a charged lepton in events with two same-flavor leptons (e or μ) and two jets, is presented. The analysis is based on proton-proton collision data, collected by the CMS Collaboration at the LHC in 2016 and corresponding to an integrated luminosity of 35.9 fb−1. No significant excess above the standard model expectation is seen in the invariant mass distribution of the dilepton plus dijet system. Assuming that couplings are identical to those of the standard model, and that only one heavy neutrino flavor NR contributes significantly to the WR decay width, the region in the two-dimensional (mWRmNR) mass plane excluded at 95% confidence level extends to approximately mWR=4.4 TeV and covers a large range of right-handed neutrino masses below the WR boson mass. This analysis provides the most stringent limits on the WR mass to date.Article Citation - WoS: 52Citation - Scopus: 55Search for a Non-Standard Higgs Boson Decaying To a Pair of New Light Bosons in Four-Muon Final States(Elsevier Ltd., 2013) Karapınar, GülerResults are reported from a search for non-standard-model Higgs boson decays to pairs of new light bosons, each of which decays into the μ+μ- final state. The new bosons may be produced either promptly or via a decay chain. The data set corresponds to an integrated luminosity of 5.3 fb-1 of proton-proton collisions at s=7 TeV, recorded by the CMS experiment at the LHC in 2011. Such Higgs boson decays are predicted in several scenarios of new physics, including supersymmetric models with extended Higgs sectors or hidden valleys. Thus, the results of the search are relevant for establishing whether the new particle observed in Higgs boson searches at the LHC has the properties expected for a standard model Higgs boson. No excess of events is observed with respect to the yields expected from standard model processes. A model-independent upper limit of 0.86±0.06 fb on the product of the cross section times branching fraction times acceptance is obtained. The results, which are applicable to a broad spectrum of new physics scenarios, are compared with the predictions of two benchmark models as functions of a Higgs boson mass larger than 86 GeV/c2 and of a new light boson mass within the range 0.25-3.55 GeV/c2. © 2013 CERN.Article Citation - WoS: 22Citation - Scopus: 38Combined Search for the Quarks of a Sequential Fourth Generation(American Physical Society, 2012) CMS Collaboration; Karapınar, GülerResults are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5fb-1 recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about ±20GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions. © 2012 CERN.Article Citation - WoS: 20Citation - Scopus: 45Search for Pair Production of First- and Second-Generation Scalar Leptoquarks in Pp Collisions at ?s=7tev(American Physical Society, 2012) CMS Collaboration; Karapınar, GülerResults are presented from a search for the pair production of first- and second-generation scalar leptoquarks in proton-proton collisions at √s=7TeV. The data sample corresponds to an integrated luminosity of 5.0fb -1, collected by the CMS detector at the LHC. The search signatures involve either two charged leptons of the same flavor (electrons or muons) and at least two jets or a single charged lepton (electron or muon), missing transverse energy, and at least two jets. If the branching fraction of the leptoquark decay into a charged lepton and a quark is assumed to be β=1, leptoquark pair production is excluded at the 95% confidence level for masses below 830 GeV and 840 GeV for the first and second generations, respectively. For β=0.5, masses below 640 GeV and 650 GeV are excluded. These limits are the most stringent to date. © 2012 CERN.