WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 8Operator-Splitting Methods Via the Zassenhaus Product Formula(Elsevier Ltd., 2011) Geiser, Juergen; Tanoğlu, Gamze; Tanoğlu, Gamze; 04.02. Department of Mathematics; 04. Faculty of Science; 01. Izmir Institute of TechnologyIn this paper, we contribute an operator-splitting method improved by the Zassenhaus product. Zassenhaus products are of fundamental importance for the theory of Lie groups and Lie algebras. While their applications in physics and physical chemistry are important, novel applications in CFD (computational fluid dynamics) arose based on the fact that their sparse matrices can be seen as generators of an underlying Lie algebra. We apply this to classical splitting and the novel Zassenhaus product formula. The underlying analysis for obtaining higher order operator-splitting methods based on the Zassenhaus product is presented. The benefits of dealing with sparse matrices, given by spatial discretization of the underlying partial differential equations, are due to the fact that the higher order commutators are very quickly computable (their matrix structures thin out and become nilpotent). When applying these methods to convection-diffusion-reaction equations, the benefits of balancing time and spatial scales can be used to accelerate these methods and take into account these sparse matrix structures. The verification of the improved splitting methods is done with numerical examples. Finally, we conclude with higher order operator-splitting methods. (C) 2010 Elsevier Inc. All rights reserved.Article Citation - WoS: 47Searches for light- and heavy-flavour three-jet resonances in Pp collisions at root S=8 Tev(Elsevier Ltd., 2014) Karapınar, Güler; Karapınar, Güler; CMS Collaboration; 01. Izmir Institute of TechnologyA search for three-jet hadronic resonance production in pp collisions at a centre-of-mass energy of 8 TeV has been conducted by the CMS Collaboration at the LHC with a data sample corresponding to an integrated luminosity of 19.4 fb(-1). The search method is model independent, and events are selected that have high jet multiplicity and large values of jet transverse momenta. The signal models explored assume R-parity-violating supersymmetric gluino pair production and have final states with either only light-flavour jets or both light- and heavy-flavour jets. No significant deviation is found between the selected events and the expected standard model multijet and t (t) over bar background. For a gluino decaying into light-flavour jets, a lower limit of 650 GeV on the gluino mass is set at a 95% confidence level, and for a gluino decaying into one heavy- and two light-flavour jets, gluino masses between 200 and 835 GeV are, for the first time, likewise excluded. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).Article Citation - WoS: 13Search for baryon number violation in top-quark decays(Elsevier Ltd., 2014) Karapınar, Güler; Karapınar, Güler; CMS Collaboration; 01. Izmir Institute of TechnologyA search for baryon number violation (BNV) in top-quark decays is performed using pp collisions produced by the LHC at root s = 8 TeV. The top-quark decay considered in this search results in one light lepton (muon or electron), two jets, but no neutrino in the final state. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.5 fb(-1). The event selection is optimized for top quarks produced in pairs, with one undergoing the BNV decay and the other the standard model hadronic decay to three jets. No significant excess of events over the expected yield from standard model processes is observed. The upper limits at 95% confidence level on the branching fraction of the BNV top-quark decay are calculated to be 0.0016 and 0.0017 for the muon and the electron channels, respectively. Assuming lepton universality, an upper limit of 0.0015 results from the combination of the two channels. These limits are the first that have been obtained on a BNV process involving the top quark. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY licenseArticle Citation - WoS: 4Asymptotic Formulae for the Schrodinger Operator With Dirichlet and Neumann Boundary Conditions(Elsevier Ltd., 2005) Karakilic, S; Atılgan, Şirin; Veliev, OA; 01. Izmir Institute of TechnologyIn this paper, we consider the Schrodinger operators defined by the differential expression Lu = -Delta u+q(x)u in d-dimensional parallelepiped F, with the Dirichlet and Neumann boundary conditions, and obtain the asymptotic formulae for the eigenvalues of these operators.Article On the Stability of the Residual-Free Bubbles for the Navier-Stokes Equations(Elsevier Ltd., 2005) Neslitürk, Ali İhsan; Neslitürk, Ali İhsan; 04.02. Department of Mathematics; 04. Faculty of Science; 01. Izmir Institute of TechnologyThis paper considers the Galerkin finite element method for the incompressible Navier-Stokes equations in two dimensions, where the finite-dimensional spaces employed consist of piecewise polynomials enriched with residual-free bubble (RFB) functions. The stability features of the residual-free bubble functions for the linearized Navier-Stokes equations are analyzed in this work. It is shown that the enrichment of the velocity space by bubble functions stabilizes the numerical method for any value of the viscosity parameter for triangular elements and for values of the viscosity parameter in the vanishing limit case for quadrilateral elements.Article Citation - WoS: 7Citation - Scopus: 7Output Feedback Stabilization of the Linearized Korteweg-De Vries Equation With Right Endpoint Controllers(Elsevier Ltd., 2019) Batal, Ahmet; Özsarı, Türker; Özsarı, Türker; Batal, Ahmet; 04.02. Department of Mathematics; 04. Faculty of Science; 01. Izmir Institute of TechnologyIn this paper, we prove the output feedback stabilization for the linearized Korteweg-de Vries (KdV) equation posed on a finite domain in the case the full state of the system cannot be measured. We assume that there is a sensor at the left end point of the domain capable of measuring the first and second order boundary traces of the solution. This allows us to design a suitable observer system whose states can be used for constructing boundary feedbacks acting at the right endpoint so that both the observer and the original plant become exponentially stable. Stabilization of the original system is proved in the L-2-sense, while the convergence of the observer system to the original plant is also proved in higher order Sobolev norms. The standard backstepping approach used to construct a left endpoint controller fails and presents mathematical challenges when building right endpoint controllers due to the overdetermined nature of the related kernel models. In order to deal with this difficulty we use the method of Ozsan and Batal, (2019) which is based on using modified target systems involving extra trace terms. In addition, we show that the number of controllers and boundary measurements can be reduced to one, with the cost of a slightly lower exponential rate of decay. We provide numerical simulations illustrating the efficacy of our controllers. (C) 2019 Elsevier Ltd. All rights reserved.Article Citation - WoS: 57Citation - Scopus: 62Measurement of the W Boson Helicity Fractions in the Decays of Top Quark Pairs To Lepton Plus Jets Final States Produced in Pp Collisions at Root S=8 Tev(Elsevier Ltd., 2016) Karapınar, Güler; Karapınar, Güler; CMS Collaboration; 01. Izmir Institute of TechnologyThe W boson helicity fractions from top quark decays in t (t) over bar events are measured using data from proton-proton collisions at a centre-of-mass energy of 8 TeV. The data were collected in 2012 with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.8 fb(-1). Events are reconstructed with either one muon or one electron, along with four jets in the final state, with two of the jets being identified as originating from b quarks. The measured helicity fractions from both channels are combined, yielding F-0 = 0.681 +/- 0.012 (stat) +/- 0.023 (syst), F-L = 0.323 +/- 0.008 (stat) +/- 0.014 (syst), and F-R = -0.004 +/- 0.005 (stat) +/- 0.014 (syst) for the longitudinal, left-, and right-handed components of the helicity, respectively. These measurements of the W boson helicity fractions are the most accurate to date and they agree with the predictions from the standard model. (C) 2016 The Author. Published by Elsevier B.V.Article Citation - WoS: 36Citation - Scopus: 36Combination of Searches for Heavy Resonances Decaying To Ww, Wz, Zz, Wh, and Zh Boson Pairs in Proton-Proton Collisions at Root S=8 and 13 Tev(Elsevier Ltd., 2017) Karapınar, Güler; Karapınar, Güler; 01. Izmir Institute of TechnologyA statistical combination of searches is presented for massive resonances decaying to WW, WZ, ZZ, WH, and ZH boson pairs in proton-proton collision data collected by the CMS experiment at the LHC. The data were taken at centre-of-mass energies of 8 and 13TeV, corresponding to respective integrated luminosities of 19.7 and up to 2.7 fb(-1). The results are interpreted in the context of heavy vector triplet and singlet models that mimic properties of composite-Higgs models predicting W' and Z' bosons decaying to WZ, WW, WH, and ZH bosons. A model with a bulk graviton that decays into WW and ZZ is also considered. This is the first combined search for WW, WZ, WH, and ZH resonances and yields lower limits on masses at 95% confidence level for W' and Z' singlets at 2.3 TeV, and for a triplet at 2.4TeV. The limits on the production cross section of a narrow bulk graviton resonance with the curvature scale of the warped extra dimension (K)over-tilde = 0.5, in the mass range of 0.6 to 4.0TeV, are the most stringent published to date. (c) 2017 The Author(s). Published by Elsevier B.V.Article Citation - WoS: 40Citation - Scopus: 50Search for Heavy Gauge W ' Bosons in Events With an Energetic Lepton and Large Missing Transverse Momentum at Root S=13tev(Elsevier Ltd., 2017) Karapınar, Güler; Karapınar, Güler; CMS Collaboration; 01. Izmir Institute of TechnologyA search is presented for W' bosons in events with an electron or muon and large missing transverse momentum, using proton-proton collision data at root s = 13 TeV collected with the CMS detector in 2015 and corresponding to an integrated luminosity of 2.3 fb(-1). No evidence of an excess of events relative to the standard model expectations is observed. For a W' boson described by the sequential standard model, upper limits at 95% confidence level are set on the product of the production cross section and branching fraction and lower limits are established on the new boson mass. Masses below 4.1 TeV are excluded combining electron and muon decay channels, significantly improving upon the results obtained with the 8 TeV data. Exclusion limits at 95% confidence level on the product of the W' production cross section and branching fraction are also derived in combination with the 8 TeV data. Finally, exclusion limits are set for the production of generic W' bosons decaying into this final state using a model-independent approach. (C) 2017 The Author. Published by Elsevier B.V.Article Citation - WoS: 22Citation - Scopus: 26Search for Black Holes and Other New Phenomena in High-Multiplicity Final States in Proton-Proton Collisions at Root S=13 Tev(Elsevier Ltd., 2017) Sirunyan, A. M.; Karapınar, Güler; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Karapınar, Güler; CMS Collaboration; 01. Izmir Institute of TechnologyA search for new physics in energetic, high-multiplicity final states has been performed using proton-proton collision data collected with the CMS detector at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 2.3 fb(-1). The standard model background, dominated by multijet production, is determined exclusively from control regions in data. No statistically significant excess of events is observed. Model-independent limits on the product of the cross section and the acceptance of a new physics signal in these final states are set and further interpreted in terms of limits on the production of black holes. Semiclassical black holes and string balls with masses as high as 9.5 TeV, and quantum black holes with masses as high as 9.0 TeV are excluded by this search in the context of models with extra dimensions, thus significantly extending limits set at a center-of-mass energy of 8 TeV with the LHC Run 1 data. (c) 2017 The Author(s). Published by Elsevier B.V.