Rectorate / Rektörlük
Permanent URI for this collectionhttps://hdl.handle.net/11147/6849
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Article Citation - WoS: 100Citation - Scopus: 81Search for Physics Beyond the Standard Model in Final States With a Lepton and Missing Transverse Energy in Proton-Proton Collisions at Root S = 8 Tev(American Physical Society, 2015) Karapınar, Güler; Karapınar, Güler; Demir, Durmuş Ali; 04.05. Department of Pyhsics; 01. Izmir Institute of Technology; 04. Faculty of ScienceA search for new physics in proton-proton collisions having final states with an electron or muon and missing transverse energy is presented. The analysis uses data collected in 2012 with the CMS detector, at an LHC center-of-mass energy of 8 TeV, and corresponding to an integrated luminosity of 19.7 fb(-1). No significant deviation of the transverse mass distribution of the charged lepton-neutrino system from the standard model prediction is found. Mass exclusion limits of up to 3.28 TeVat 95% confidence level for a W0-boson with the same couplings as that of the standard model W-boson are determined. Results are also derived in the framework of split universal extra dimensions, and exclusion limits on Kaluza-Klein Wd(KK)((2)) states are found. The final state with large missing transverse energy also enables a search for dark matter production with a recoiling W-boson, with limits set on the mass and the production cross section of potential candidates. Finally, limits are established for a model including interference between a left-handed W'-boson and the standard model W-boson and for a compositeness model.Article Citation - WoS: 45Citation - Scopus: 47Search for Stopped Gluinos in Pp Collisions at ?s=7tev(American Physical Society, 2011) Karapınar, Güler; Demir, Durmuş Ali; Karapınar, Güler; 04.05. Department of Pyhsics; 01. Izmir Institute of Technology; 04. Faculty of ScienceThe results of the first search for long-lived gluinos produced in 7 TeV pp collisions at the CERN Large Hadron Collider are presented. The search looks for evidence of long-lived particles that stop in the CMS detector and decay in the quiescent periods between beam crossings. In a dataset with a peak instantaneous luminosity of 1×1032cm-2s-1, an integrated luminosity of 10pb-1, and a search interval corresponding to 62 hours of LHC operation, no significant excess above background was observed. Limits at the 95% confidence level on gluino pair production over 13 orders of magnitude of gluino lifetime are set. For a mass difference m g-mχ10>100GeV/c2, and assuming BR(g→gχ10)= 100%, mg<370GeV/c2 are excluded for lifetimes from 10μs to 1000 s. © 2010 The American Physical Society.Article Citation - WoS: 77Citation - Scopus: 86Measurement of the Isolated Prompt Photons Production Cross Section in Pp Collisions at ?s=7tev(American Physical Society, 2011) Karapınar, Güler; Karapınar, Güler; Demir, Durmuş Ali; 04.05. Department of Pyhsics; 01. Izmir Institute of Technology; 04. Faculty of ScienceThe differential cross section for the inclusive production of isolated prompt photons has been measured as a function of the photon transverse energy ETγ in pp collisions at √s=7TeV using data recorded by the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 2.9pb-1. Photons are required to have a pseudorapidity |ηγ|<1.45 and ETγ>21GeV, covering the kinematic region 0.006<xT<0.086. The measured cross section is found to be in agreement with next-to-leading-order perturbative QCD calculations. © 2011 American Physical Society.Article Citation - WoS: 87Citation - Scopus: 115Measurement of the B+ Production Cross Section in Pp Collisions at ?s=7tev(American Physical Society, 2011) Karapınar, Güler; Demir, Durmuş Ali; Karapınar, Güler; 04.05. Department of Pyhsics; 01. Izmir Institute of Technology; 04. Faculty of ScienceMeasurements of the total and differential cross sections dσ/dpTB and dσ/dyB for B+ mesons produced in pp collisions at √s=7TeV are presented. The data correspond to an integrated luminosity of 5.8pb-1 collected by the CMS experiment operating at the LHC. The exclusive decay B+→J/ψK+, with J/ψ→μ+μ-, is used to detect B+ mesons and to measure the production cross section as a function of pTB and yB. The total cross section for pTB>5GeV and |yB|<2.4 is measured to be 28.1±2.4±2.0±3.1μb, where the first uncertainty is statistical, the second is systematic, and the last is from the luminosity measurement. © 2011 American Physical Society.Article Citation - WoS: 56Citation - Scopus: 81Dijet Azimuthal Decorrelations in Pp Collisions at ?s=7tev(American Physical Society, 2011) Karapınar, Güler; Karapınar, Güler; Demir, Durmuş Ali; 04.05. Department of Pyhsics; 01. Izmir Institute of Technology; 04. Faculty of ScienceMeasurements of dijet azimuthal decorrelations in pp collisions at √s=7TeV using the CMS detector at the CERN LHC are presented. The analysis is based on an inclusive dijet event sample corresponding to an integrated luminosity of 2.9pb-1. The results are compared to predictions from perturbative QCD calculations and various Monte Carlo event generators. The dijet azimuthal distributions are found to be sensitive to initial-state gluon radiation. © 2011 CERN, for the CMS Collaboration.Article Citation - WoS: 20Citation - Scopus: 19Search for Pair Production of Second-Generation Scalar Leptoquarks in Pp Collisions at ?s=7tev(American Physical Society, 2011) Karapınar, Güler; Demir, Durmuş Ali; Karapınar, Güler; 04.05. Department of Pyhsics; 01. Izmir Institute of Technology; 04. Faculty of ScienceA search for pair production of second-generation scalar leptoquarks in the final state with two muons and two jets is performed using proton-proton collision data at √s=7TeV collected by the CMS detector at the LHC. The data sample used corresponds to an integrated luminosity of 34pb-1. The number of observed events is in good agreement with the predictions from the standard model processes. An upper limit is set on the second-generation leptoquark cross section times β2 as a function of the leptoquark mass, and leptoquarks with masses below 394 GeV are excluded at a 95% confidence level for β=1, where β is the leptoquark branching fraction into a muon and a quark. These limits are the most stringent to date.© 2011 American Physical Society.Article Citation - WoS: 26Citation - Scopus: 28Search for Pair Production of First-Generation Scalar Leptoquarks in Pp Collisions at ?s=7tev(American Physical Society, 2011) Karapınar, Güler; Karapınar, Güler; Demir, Durmuş Ali; 04.05. Department of Pyhsics; 01. Izmir Institute of Technology; 04. Faculty of ScienceA search for pair production of first-generation scalar leptoquarks is performed in the final state containing two electrons and two jets using proton-proton collision data at √s=7TeV. The data sample used corresponds to an integrated luminosity of 33pb-1 collected with the CMS detector at the CERN LHC. The number of observed events is in good agreement with the predictions for the standard model background processes, and an upper limit is set on the leptoquark pair production cross section times β2 as a function of the leptoquark mass, where β is the branching fraction of the leptoquark decay to an electron and a quark. A 95% confidence level lower limit is set on the mass of a first-generation scalar leptoquark at 384 GeV for β=1, which is the most stringent direct limit to date. © 2011 American Physical Society.Article Citation - WoS: 58Citation - Scopus: 72Measurement of Dijet Angular Distributions and Search for Quark Compositeness in Pp Collisions at ?s=77tev(American Physical Society, 2011) Karapınar, Güler; Karapınar, Güler; Demir, Durmuş Ali; 04.05. Department of Pyhsics; 01. Izmir Institute of Technology; 04. Faculty of ScienceDijet angular distributions are measured over a wide range of dijet invariant masses in pp collisions at √s=7TeV, at the CERN LHC. The event sample, recorded with the CMS detector, corresponds to an integrated luminosity of 36pb-1. The data are found to be in good agreement with the predictions of perturbative QCD, and yield no evidence of quark compositeness. With a modified frequentist approach, a lower limit on the contact interaction scale for left-handed quarks of Λ+=5.6TeV (Λ -=6.7TeV) for destructive (constructive) interference is obtained at the 95% confidence level. © 2011 American Physical Society.Article Citation - WoS: 95Citation - Scopus: 117Upsilon Production Cross Section in Pp Collisions at ?s=7tev(American Physical Society, 2011) Karapınar, Güler; Karapınar, Güler; Demir, Durmuş Ali; 04.05. Department of Pyhsics; 01. Izmir Institute of Technology; 04. Faculty of ScienceThe Υ(1S), Υ(2S), and Υ(3S) production cross sections in proton-proton collisions at √s=7TeV are measured using a data sample collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 3.1±0.3pb -1. Integrated over the rapidity range |y|<2, we find the product of the Υ(1S) production cross section and branching fraction to dimuons to be σ(pp→Υ(1S)X) •B(Υ(1S)→μ +μ -)=7.37±0.13-0. 42+0.61±0.81nb, where the first uncertainty is statistical, the second is systematic, and the third is associated with the estimation of the integrated luminosity of the data sample. This cross section is obtained assuming unpolarized Υ(1S) production. With the assumption of fully transverse or fully longitudinal production polarization, the measured cross section changes by about 20%. We also report the measurement of the Υ(1S), Υ(2S), and Υ(3S) differential cross sections as a function of transverse momentum and rapidity. © 2011 American Physical Society.Article Citation - WoS: 44Citation - Scopus: 48Search for Supersymmetry in Pp Collisions at ?s=7tev in Events With Two Photons and Missing Transverse Energy(American Physical Society, 2011) Karapınar, Güler; Demir, Durmuş Ali; Karapınar, Güler; 04.05. Department of Pyhsics; 01. Izmir Institute of Technology; 04. Faculty of ScienceA search for supersymmetry in the context of general gauge-mediated breaking with the lightest neutralino as the next-to-lightest supersymmetric particle and the gravitino as the lightest is presented. The data sample corresponds to an integrated luminosity of 36pb-1 recorded by the CMS experiment at the LHC. The search is performed by using events containing two or more isolated photons, at least one hadronic jet, and significant missing transverse energy. No excess of events at high missing transverse energy is observed. Upper limits on the signal cross section for general gauge-mediated supersymmetry between 0.3 and 1.1 pb at the 95% confidence level are determined for a range of squark, gluino, and neutralino masses, excluding supersymmetry parameter space that was inaccessible to previous experiments. © 2011 American Physical Society.
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