WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

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Author: search.filters.author.Karapınar, GülerScopus Q: search.filters.scopusQuartile.Q2

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Now showing 1 - 7 of 7
  • Article
    Citation - WoS: 3
    Fragmentation of J/Psi in jets in pp collisions at root S=5.02 TeV batoul diab for the CMS collaboration
    (Elsevier Ltd., 2019) Karapınar, Güler; CMS Collaboration
    The fragmentation of jets containing a J/psi meson is studied in root s = 5.02 TeV pp data using an integrated luminosity of L = 27.39 pb(-1). The fraction of the jet transverse momentum p(Tjet) carried by the J/psi is measured for prompt J/psi and J/psi coming from b hadron decays, named nonprompt. Whereas the fragmentation function of nonprompt J/psi is well-modeled by simulations using a Monte Carlo generator, the prompt J/psi are found to be accompanied by a larger level of jet activity. The fraction of J/psi mesons that are produced inside a jet is also reported, and found to be larger in data than in simulation, for both prompt and nonprompt J/psi.
  • Article
    Citation - WoS: 9
    Evidence for Light-By Scattering in Ultraperipheral Pbpb Collisions at Root S-Nn=5.02 Tev
    (Elsevier Ltd., 2019) Karapınar, Güler; CMS Collaboration
    Evidence for light-by-light (LbL) scattering, gamma gamma -> gamma gamma, in ultraperipheral PbPb collisions at a nucleon-nucleon center of-mass energy of 5.02 TeV is reported. LbL scattering processes are selected in events with just two photons produced, with transverse energy E-T(gamma) > 2 GeV, pseudorapidity vertical bar eta(gamma)vertical bar < 2.4; and diphoton invariant mass m(gamma gamma) > 5 GeV, transverse momentum p(T)(gamma gamma) < 1 GeV, and acoplanarity (1 - Delta phi(gamma gamma)/pi) < 0.01. After all selection criteria, 14 events are observed, compared to 11.1 +/- 1.1 (theo) and 3.8 +/- 1.3 (stat) events expected for signal and background processes respectively. The significance of the signal excess over the background-only hypothesis is 4.10 sigma. The measured fiducial LbL scattering cross section, sigma(fid)(gamma gamma -> gamma gamma) = 122 +/- 46 (stat) +/- 29 (syst) +/- 4 (theo) nb is consistent with the standard model prediction.
  • Article
    Beyond Npdfs Effects : Prompt J/Psi and Psi(2s) Production in Ppb and Pp Collisions
    (Elsevier Ltd., 2019) CMS Collaboration; Karapınar, Güler
    A multi-dimensional analysis of prompt charmonia in pp and pPb collisions at root s(NN) = 5.02 TeV with the CMS detector is presented. The pPb differential cross-sections of prompt J/psi are shown in a wide kinematic region, for transverse momentum p(T) spanning from 2 to 30 GeV/c and a rapidity interval between -2.4 to 1.93 in the center of mass of the collision. The final results on prompt psi/(2S) meson production cross section in pp and pPb collisions at 5.02 TeV are also reported as a function of p(T) and rapidity, for p(T) from 4 to 30 GeV/c. The nuclear modification factor is found to be smaller than that of prompt J/psi in all measured bins, especially at low p(T) and at backward rapidity. Such a different behaviour between the ground and excited states cannot be reproduced considering nPDF effects alone.
  • Article
    Measurement of Anisotropic Flow in Xexe Collisions at 5.44 Tev With the Cms Experiment
    (Elsevier Ltd., 2019) Karapınar, Güler; CMS Collaboration
    New measurements of anisotropic flow in XeXe collisions at a center-of-mass energy of 5.44 TeV per nucleon pair, collected by the CMS experiment at the LHC, are presented. The v(2), v(3) and v(4) Fourier coefficients of the anisotropic azimuthal distribution are obtained employing three different analysis techniques: two-particle correlations, the scalar product method, and multiparticle cumulants, which have different sensitivities to non-flow and flow fluctuation effects. The results are shown as a function of transverse momentum (P-T) for various centrality selections, and compared with corresponding results from PbPb collisions. These new measurements in a smaller nucleus-nucleus system than PbPb provide additional insights into the system-size dependence of the collective flow induced by the dominant collision geometry and its fluctuations. In particular, these results, compared to theoretical predictions and Monte Carlo generators, will provide important details on the system size dependence of the medium response in heavy ion collisions. They also offer a unique opportunity to study the onset of flow from small to large systems.
  • Article
    Multiparticle Correlations and Higher Order Harmonics in Ppb Collisions at Root S(nn)=8.16 Tev
    (Elsevier Ltd., 2019) Karapınar, Güler; CMS Collaboration
    The elliptic and higher-order azimuthal anisotropy Fourier harmonics (v(n)) are obtained for pPb collisions at root s(NN) = 8.16 TeV over a wide range of event multiplicities based on multiparticle correlations. The data were collected by the CMS experiment during the 2016 LHC run. A sample of peripheral PbPb collisions at root s(NN) = 5.02 TeV covering a similar range of event multiplicities to the pPb results is also analyzed for comparison. The ratios of different harmonic moments are obtained for both v(2) and v(3) with high precision, which allows a direct comparison to theoretical predictions assuming a hydrodynamic evolution of the created medium with initial-state density fluctuations, particularly probing the non-Gaussian nature of initial-state fluctuations in small collision systems. The presented results provide crucial insights into the origin of collective long-range correlations observed in small collision systems.
  • Article
    Citation - WoS: 1
    D-0 R-Aa in Pbpb Collisions at Root S(nn)=5.02 Tev and Elliptic Flow in Ppb Collisions at Root S(nn)=8.16 Tev With Cms
    (Elsevier Ltd., 2019) Karapınar, Güler; CMS Collaboration
    The study of charm production in heavy-ion collisions is considered an excellent probe for the properties of the hot and dense medium created in heavy-ion collisions. Measurements of D-0-meson nuclear modification factor can provide strong constraints into the mechanisms of in-medium energy loss and charm flow in the medium. The measurement of D-0-meson elliptic flow in pPb collisions helps us understand the strength of charm quarks coupling to significantly reduced systems which demonstrate hydrodynamic properties. In this paper, the measurements of the D-0-meson nuclear modification factor in PbPb collisions at 5.02 TeV together with the new measurement of D-0-meson elliptic flow in high multiplicity pPb collisions at 5.02 TeV using the two-particle correlation method will be presented.
  • Article
    Citation - WoS: 3
    Search for the Chiral Magnetic Effect at the Lhc With the Cms Experiment
    (Elsevier Ltd., 2019) Karapınar, Güler; CMS Collaboration
    Searches for the chiral magnetic effect (CME) using charge-dependent azimuthal correlations with respect to event planes are presented in PbPb collisions at 5.02 TeV and pPb collisions at 5.02 and 8.16 TeV, with the CMS experiment at the LHC. The azimuthal correlations with respect to the second- and third-order event planes are explored as a function of pseudorapidity, transverse momentum, and event multiplicity, which provides new insights into the underlying background correlations. By employing an event-shape engineering technique, a linear dependence of charge-dependent correlations on the second-order anisotropy flow (nu(2)) is observed, and the upper limits on the nu(2)-independent fraction, which is directly related to the CME signal, are obtained at 95% confidence level for both pPb and PbPb collisions. These results provide strong constraints on the search for the chiral magnetic effect at LHC energies, and establish new guidelines for searches in future experiments.