Rectorate / Rektörlük

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  • Article
    Citation - WoS: 26
    Citation - Scopus: 27
    Measurement of the Azimuthal Anisotropy of [Formula Presented] and [Formula Presented] Mesons in PbPb Collisions at S NN =5.02 TeV
    (Elsevier B.V., 2021) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Dragicevic, M.; De Jesus Damiao, D.; 01. Izmir Institute of Technology
    The second-order Fourier coefficients (v<inf>2</inf>) characterizing the azimuthal distributions of [Formula presented] and [Formula presented] mesons produced in PbPb collisions at s<inf> <inf>NN</inf> </inf>=5.02TeV are studied. The [Formula presented] mesons are reconstructed in their dimuon decay channel, as measured by the CMS detector. The collected data set corresponds to an integrated luminosity of 1.7nb−1. The scalar product method is used to extract the v<inf>2</inf> coefficients of the azimuthal distributions. Results are reported for the rapidity range |y|<2.4, in the transverse momentum interval 0<p<inf>T</inf><50GeV/c, and in three centrality ranges of 10–30%, 30–50% and 50–90%. In contrast to the J/ψ mesons, the measured v<inf>2</inf> values for the [Formula presented] mesons are found to be consistent with zero. © 2021 The Author(s)
  • Article
    Citation - WoS: 59
    Measurement of the Upsilon(1s), Upsilon(2s), and Upsilon(3s) Cross Sections in Pp Collisions at Root S=7 Tev
    (Elsevier Ltd., 2013) Karapınar, Güler; Karapınar, Güler; 01. Izmir Institute of Technology
    The Upsilon(1S), Upsilon(2S), and Upsilon(3S) production cross sections are measured using a data sample corresponding to an integrated luminosity of 35.8 +/- 1.4 pb(-1) of proton-proton collisions at root s = 7 TeV, collected with the CMS detector at the LHC. The Upsilon resonances are identified through their decays to dimuons. Integrated over the Upsilon transverse momentum range p(T)(Upsilon) < 50 GeV/c and rapidity range vertical bar y(Upsilon)vertical bar < 2.4, and assuming unpolarized Upsilon production, the products of the Upsilon production cross sections and dimuon branching fractions are sigma (pp -> Upsilon(1S)X) . B(Upsilon(1S) -> mu(+)mu(-)) = (8.55 +/- 0.05(-0.50)(+0.56) +/- 0.34) nb, sigma (pp -> Upsilon(2S)X) . B(Upsilon(2S) -> mu(+)mu(-)) = (2.21 +/- 0.03(-0.14)(+0.16) +/- 0.09) nb, sigma (pp -> Upsilon(3S)X) . B(Upsilon(3S) -> mu(+)mu(-)) = (1.11 +/- 0.02(-0.08)(+0.10) +/- 0.04) nb, where the first uncertainty is statistical, the second is systematic, and the third is from the uncertainty in the integrated luminosity. The differential cross sections in bins of transverse momentum and rapidity, and the cross section ratios are presented. Cross section measurements performed within a restricted muon kinematic range and not corrected for acceptance are also provided. These latter measurements are independent of Upsilon polarization assumptions. The results are compared to theoretical predictions and previous measurements. (C) 2013 CERN. Published by Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 16
    Citation - Scopus: 68
    Measurement of the Y(1s) Pair Production Cross Section and Search for Resonances Decaying To Y(1s)μ+μ− in Proton-Proton Collisions at S=13tev
    (Elsevier B.V., 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Dudko, L.; 01. Izmir Institute of Technology
    The fiducial cross section for Y(1S) pair production in proton-proton collisions at a center-of-mass energy of 13 TeV in the region where both Y(1S) mesons have an absolute rapidity below 2.0 is measured to be 79±11(stat)±6(syst)±3(B) pb assuming the mesons are produced unpolarized. The last uncertainty corresponds to the uncertainty in the Y(1S) meson dimuon branching fraction. The measurement is performed in the final state with four muons using proton-proton collision data collected in 2016 by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9fb−1. This process serves as a standard model reference in a search for narrow resonances decaying to Y(1S)μ+μ− in the same final state. Such a resonance could indicate the existence of a tetraquark that is a bound state of two b quarks and two b¯ antiquarks. The tetraquark search is performed for masses in the vicinity of four times the bottom quark mass, between 17.5 and 19.5 GeV, while a generic search for other resonances is performed for masses between 16.5 and 27 GeV. No significant excess of events compatible with a narrow resonance is observed in the data. Limits on the production cross section times branching fraction to four muons via an intermediate Y(1S) resonance are set as a function of the resonance mass. © 2020 The Author(s)
  • Article
    Citation - WoS: 39
    Citation - Scopus: 40
    Measurements of the ϒ(1s), ϒ(2s), and ϒ(3s) Differential Cross Sections in Pp Collisions at S=7tev
    (Elsevier B.V., 2015) Khachatryan, V.; Karapınar, Güler; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Krajczar, K.; 01. Izmir Institute of Technology
    Differential cross sections as a function of transverse momentum pT are presented for the production of ϒ(nS) (n = 1, 2, 3) states decaying into a pair of muons. Data corresponding to an integrated luminosity of 4.9fb−1 in pp collisions at s=7TeV were collected with the CMS detector at the LHC. The analysis selects events with dimuon rapidity |y| <1.2 and dimuon transverse momentum in the range 10 <pT <100GeV. The measurements show a transition from an exponential to a power-law behavior at pT≈20GeV for the three ϒ states. Above that transition, the ϒ(3S) spectrum is significantly harder than that of the ϒ(1S). The ratios of the ϒ(3S) and ϒ(2S) differential cross sections to the ϒ(1S) cross section show a rise as pT increases at low pT, then become flatter at higher pT. © 2015 CERN for the benefit of the CMS Collaboration