PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article Citation - WoS: 5Citation - Scopus: 9Search for Resonances Decaying To Three W Bosons in Proton-Proton Collisions at Root S=13 Tev(American Physical Society, 2022) Karapınar, Güler; Karapınar, Güler; CMS Collaboration; 01. Izmir Institute of TechnologyA search for resonances decaying into a W boson and a radion, where the radion decays into two W bosons, is presented. The data analyzed correspond to an integrated luminosity of 138 fb???1 recorded in ffiffiproton-proton collisions with the CMS detector at p s 1/4 13 TeV. One isolated charged lepton is required, together with missing transverse momentum and one or two massive large-radius jets, containing the decay products of either two or one W bosons, respectively. No excess over the background estimation is observed. The results are combined with those from a complementary channel with an all-hadronic final state, described in an accompanying paper. Limits are set on parameters of an extended warped extradimensional model. These searches are the first of their kind at the LHC.Article Citation - WoS: 25Citation - Scopus: 32Using Z Boson Events To Study Parton-Medium Interactions in Pb-Pb Collisions(American Physical Society, 2022) Karapınar, Güler; Karapınar, Güler; 01. Izmir Institute of TechnologyThe spectra measurements of charged hadrons produced in the shower of a parton originating in the same hard scattering with a leptonically decaying Z boson arc reported in lead-lead nuclei (Pb-Pb) and proton-proton (pp) collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Both Pb-Pb and pp data sets are recorded by the CMS experiment at the LHC and correspond to an integrated luminosity of 1.7 nb(-1) and 320 pb(-1), respectively. Hadronic collision data with one reconstructed Z boson candidate with the transverse momentum p(T) > 30 GeV/c are analyzed. The Z boson constrains the initial energy and direction of the associated parton. In heavy ion events, azimuthal angular distributions of charged hadrons with respect to the direction of a Z boson are sensitive to modifications of the in-medium parton shower and medium response. compared to reference data from pp interactions, the results for central Pb-Pb collisions indicate a modification of the angular correlations. The measurements of the fragmentation functions and p(T) spectra of charged particles in Z boson events, which are sensitive to medium modifications of the parton shower longitudinal structure, are also reported. Significant modifications in central Pb-Pb events compared to the pp reference data are also found for these observables.Article Citation - WoS: 15Citation - Scopus: 21Measurements of the Electroweak Diboson Production Cross Sections in Proton-Proton Collisions at Root S=5.02 Tev Using Leptonic Decays(American Physical Society, 2021) Karapınar, Güler; Karapınar, Güler; CMS Collaboration; 01. Izmir Institute of TechnologyThe first measurements of diboson production cross sections in proton-proton interactions at a center-of-mass energy of 5.02 TeV are reported. They are based on data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 302 pb(-1). Events with two, three, or four charged light leptons (electrons or muons) in the final state are analyzed. The WW, WZ, and ZZ total cross sections are measured as sigma(WW) = 37:0(-5.2)(+5.5) (stat)(-2.6)(+2.7) (syst) pb, sigma(WZ) = 6.4(-2.1)(+2.5) (stat)(-0.3)(+0.5)(syst) pb, and sigma(ZZ) = 5.3(-2.1)(+2.5)(stat)(-0.4)(+0.5) (syst) pb. All measurements are in good agreement with theoretical calculations at combined next-to-next-to-leading order quantum chromodynamics and next-to-leading order electroweak accuracy.Article Citation - WoS: 32Citation - Scopus: 42Search for Long-Lived Particles Decaying in the Cms End Cap Muon Detectors in Proton-Proton Collisions at Root S=13 Tev(American Physical Society, 2021) Karapınar, Güler; Karapınar, Güler; CMS Collaboration; 01. Izmir Institute of TechnologyA search for long-lived particles (LLPs) produced in decays of standard model (SM) Higgs bosons is presented. The data sample consists of 137 fb(-1) of proton-proton collisions at root s = 13 TeV, recorded at the LHC in 2016-2018. A novel technique is employed to reconstruct decays of LLPs in the end cap muon detectors. The search is sensitive to a broad range of LLP decay modes and to masses as low as a few GeV. No excess of events above the SM background is observed. The most stringent limits to date on the branching fraction of the Higgs boson to LLPs subsequently decaying to quarks and tau(+)tau(-) are found for proper decay lengths greater than 6, 20, and 40 m, for LLP masses of 7, 15, and 40 GeV, respectively.Article Citation - WoS: 73Measurement of the Polarization of W Bosons With Large Transverse Momenta in W Plus Jets Events at the Lhc(American Physical Society, 2011) Karapınar, Güler; Karapınar, Güler; 01. Izmir Institute of TechnologyA first measurement of the polarization of W bosons with large transverse momenta in pp collisions is presented. The measurement is based on 36 pb(-1) of data recorded at root s = 7 TeV by the CMS detector at the LHC. The left-handed, right-handed, and longitudinal polarization fractions (f(L), f(R), and f(0), respectively) of W bosons with transverse momenta larger than 50 GeV are determined by using decays to both electrons and muons. The muon final state yields the most precise measurement: (f(L) - f(R))(-) = 0.240 +/- 0.036(syst) +/- 0.031(syst) and f(0)(-) = 0.183 +/- 0.087(stat) +/- 0.123(syst) for negatively charged W bosons and (f(L) - f(R))(+) = 0.310 +/- 0.036(syst) +/- 0.017(syst) and f(0)(+) = 0.171 +/- 0.085(syst) +/- 0.099(syst) for positively charged W bosons. This establishes, for the first time, that W bosons produced in pp collisions with large transverse momenta are predominantly left-handed, as expected in the standard model.Article Citation - WoS: 47Search for Heavy Neutrinos and W-R Bosons With Right-Handed Couplings in a Left-Right Symmetric Model in Pp Collisions at Root S=7 Tev(American Physical Society, 2012) Karapınar, Güler; 01. Izmir Institute of TechnologyResults are presented from a search for heavy, right-handed muon neutrinos, N-mu, and right-handed W-R bosons, which arise in the left-right symmetric extensions of the standard model. The analysis is based on a 5: 0 fb(-1) sample of proton-proton collisions at a center-of-mass energy of 7 TeV, collected by the CMS detector at the Large Hadron Collider. No evidence is observed for an excess of events over the standard model expectation. For models with exact left-right symmetry, heavy right-handed neutrinos are excluded at 95% confidence level for a range of neutrino masses below the WR mass, dependent on the value of M-WR. The excluded region in the two-dimensional (M-WR, MN mu) mass plane extends to M-WR = 2.5TeV. DOI: 10.1103/PhysRevLett.109.261802Article Citation - WoS: 20Measurement of the Azimuthal Anisotropy of Neutral Pions in Pb-Pb Collisions at Root S-Nn=2.76 Tev(American Physical Society, 2013) Karapınar, Güler; Karapınar, Güler; 01. Izmir Institute of TechnologyFirst measurements of the azimuthal anisotropy of neutral pions produced in Pb-Pb collisions at a center-of-mass energy of root S-NN = 2.76 TeV are presented. The amplitudes of the second Fourier component (upsilon(2)) of the pi(0) azimuthal distributions are extracted using an event-plane technique. The values of upsilon(2) are studied as a function of the neutral pion transverse momentum (p(T)) for different classes of collision centrality in the kinematic range 1.6< p(T)<8.0 GeV/c, within the pseudorapidity interval vertical bar eta vertical bar < 0.8. The CMS measurements of upsilon(2)(p(T)) are similar to previously reported pi(0) azimuthal anisotropy results from root S-NN = 200 GeV Au-Au collisions at RHIC, despite a factor of similar to 14 increase in the centerof-mass energy. In the momentum range 2.5<p(T)<5.0 GeV/c, the neutral pion anisotropies are found to be smaller than those observed by CMS for inclusive charged particles. DOI: 10.1103/PhysRevLett.110.042301Article Citation - WoS: 131Evidence for Associated Production of a Single Top Quark and W Boson in Pp Collisions at Root S=7 Tev(American Physical Society, 2013) Karapınar, Güler; Karapınar, Güler; 01. Izmir Institute of TechnologyEvidence is presented for the associated production of a single top quark and W boson in pp collisions at root s = 7 TeV with the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 4.9 fb(-1). The measurement is performed using events with two leptons and a jet originated from a b quark. A multivariate analysis based on kinematic properties is utilized to separate the t (t) over bar background from the signal. The observed signal has a significance of 4.0 sigma and corresponds to a cross section of 16(-4)(+5) pb, in agreement with the standard model expectation of 15.6 +/- 0.4(-1.2)(+1.0) pb. DOI: 10.1103/PhysRevLett.110.022003Article Citation - WoS: 47Search for Pair Production of Third-Generation Leptoquarks and Top Squarks in Pp Collisions at Root S=7 Tev(American Physical Society, 2013) Karapınar, Güler; Karapınar, Güler; 01. Izmir Institute of TechnologyResults are presented from a search for the pair production of third-generation scalar and vector leptoquarks, as well as for top squarks in R-parity-violating supersymmetric models. In either scenario, the new, heavy particle decays into a tau lepton and a b quark. The search is based on a data sample of pp collisions at root s = 7 TeV, which is collected by the CMS detector at the LHC and corresponds to an integrated luminosity of 4.8 fb(-1). The number of observed events is found to be in agreement with the standard model prediction, and exclusion limits on mass parameters are obtained at the 95% confidence level. Vector leptoquarks with masses below 760 GeV are excluded and, if the branching fraction of the scalar leptoquark decay to a tau lepton and a b quark is assumed to be unity, third-generation scalar leptoquarks with masses below 525 GeV are ruled out. Top squarks with masses below 453 GeV are excluded for a typical benchmark scenario, and limits on the coupling between the top squark, tau lepton, and b quark, lambda'(333) are obtained. These results are the most stringent for these scenarios to date. DOI: 10.1103/PhysRevLett.110.081801Article Citation - WoS: 303Study of the Mass and Spin-Parity of the Higgs Boson Candidate Via Its Decays To Z Boson Pairs(American Physical Society, 2013) Karapınar, Güler; Karapınar, Güler; 01. Izmir Institute of TechnologyA study is presented of the mass and spin-parity of the new boson recently observed at the LHC at a mass near 125 GeV. An integrated luminosity of 17: 3 fb(-1), collected by the CMS experiment in proton-proton collisions at center-of-mass energies of 7 and 8 TeV, is used. The measured mass in the ZZ channel, where both Z bosons decay to e or mu pairs, is 126: 2 +/- 0.6(stat) +/- 0. 2(syst) GeV. The angular distributions of the lepton pairs in this channel are sensitive to the spin-parity of the boson. Under the assumption of spin 0, the present data are consistent with the pure scalar hypothesis, while disfavoring the pure pseudoscalar hypothesis. DOI: 10.1103/PhysRevLett.110.081803