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DSpace dijital arşiv sistemi toplar, depolar, dizinler, korur ve dijital araştırma materyallerini dağıtmaya aracılık eder.Mon, 28 May 2018 09:50:17 GMT2018-05-28T09:50:17ZFinite difference time domain formulation for epsilon-negative medium using wave equation
http://hdl.handle.net/11376/3117
Finite difference time domain formulation for epsilon-negative medium using wave equation
Pekmezci, Ayşegül; Topuz, Ercan; Sevgi, Levent
A novel approach utilizing one-dimensional (1D) wave equation based finite difference time domain (FDTD) formulations for Lorentz-type Epsilon-Negative (ENG) medium is developed. To demonstrate the validity and accuracy of the formulation, reflection of a plane wave normally incident at free spaceENG interface is compared with the analytical solution. Moreover, propagation characteristics of Lorentz-type ENG medium is investigated using the FDTD formulations both for wave equation and Maxwell's curl equations in 1D case. Comparisons of memory and computational time requirements of both formulations are given.
Pekmezci, Ayşegül (Dogus Author) -- Topuz, Ercan (Dogus Author)
Sun, 01 May 2016 00:00:00 GMThttp://hdl.handle.net/11376/31172016-05-01T00:00:00ZA new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector
http://hdl.handle.net/11376/3116
A new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector
Çetin, Serkant Ali; ATLAS Collaboration
The distribution of particles inside hadronic jets produced in the decay of boosted W and Z bosons can be used to discriminate such jets from the continuum background. Given that a jet has been identified as likely resulting from the hadronic decay of a boosted W or Z boson, this paper presents a technique for further differentiating Z bosons from W bosons. The variables used are jet mass, jet charge, and a b-tagging discriminant. A likelihood tagger is constructed from these variables and tested in the simulation of W' -> WZ for bosons in the transverse momentum range 200 GeV < p(T) < 400 GeV in root s = 8 TeV pp collisions with the ATLAS detector at the LHC. For Z-boson tagging efficiencies of epsilon(Z) = 90, 50, and 10 %, one can achieve W+-boson tagging rejection factors (1/epsilon(W+)) of 1.7, 8.3 and 1000, respectively. It is not possible to measure these efficiencies in the data due to the lack of a pure sample of high p(T), hadronically decaying Z bosons. However, the modelling of the tagger inputs for boosted W bosons is studied in data using a t (t) over bar -enriched sample of events in 20.3 fb(-1) of data at root s = 8 TeV. The inputs are well modelled within uncertainties, which builds confidence in the expected tagger performance.
Çetin, Serkant Ali (Dogus Author)
Thu, 28 Apr 2016 00:00:00 GMThttp://hdl.handle.net/11376/31162016-04-28T00:00:00ZAnalysis of periodic line arrays of phased dipoles with band-limited excitations
http://hdl.handle.net/11376/3115
Analysis of periodic line arrays of phased dipoles with band-limited excitations
Uluışık, Çağatay
Radiation from periodic line arrays of sequentially excited electric current dipoles is investigated in time domain. The time domain Floquet wave representations are reviewed for a semi-infinite line array. In this study, the excitation function is chosen as a normalized Rayleigh pulse which does not contain significant low frequency components. The Floquet wave representation for band limited excitations includes a time consuming convolution operation which has to be performed numerically. To avoid the numerical convolution the normalized Rayleigh pulse is represented approximately via a set of linear/quadratic functions. This results in substantial reduction in the computation time since the convolution can be calculated analytically.
Uluışık, Çağatay (Dogus Author)
Sun, 01 May 2016 00:00:00 GMThttp://hdl.handle.net/11376/31152016-05-01T00:00:00ZObservation of Long-Range Elliptic Azimuthal Anisotropies in root s=13 and 2.76 TeV pp Collisions with the ATLAS Detector
http://hdl.handle.net/11376/3114
Observation of Long-Range Elliptic Azimuthal Anisotropies in root s=13 and 2.76 TeV pp Collisions with the ATLAS Detector
Çetin, Serkant Ali; ATLAS Collaboration
ATLAS has measured two-particle correlations as a function of the relative azimuthal angle, Delta phi, and pseudorapidity, Delta eta, in root s = 13 and 2.76 TeV pp collisions at the LHC using charged particles measured in the pseudorapidity interval vertical bar eta vertical bar < 2.5. The correlation functions evaluated in different intervals of measured charged-particle multiplicity show a multiplicity-dependent enhancement at Delta phi similar to 0 that extends over a wide range of Delta eta, which has been referred to as the "ridge." Per-trigger-particle yields, Y(Delta phi) are measured over 2 < vertical bar Delta eta vertical bar < 5. For both collision energies, the Y(Delta phi) distribution in all multiplicity intervals is found to be consistent with a linear combination of the per-trigger-particle yields measured in collisions with less than 2 phi reconstructed tracks, and a constant combinatoric contribution modulated by cos (2 Delta phi). The fitted Fourier coefficient, nu(2,2), exhibits factorization, suggesting that the ridge results from per-event cos (2 phi) modulation of the single-particle distribution with Fourier coefficients nu(2). The nu(2) values are presented as a function of multiplicity and transverse momentum. They are found to be approximately constant as a function of multiplicity and to have a p(T) dependence similar to that measured in p + Pb and Pb + Pb collisions. The nu(2) values in the 13 and 2.76 TeV data are consistent within uncertainties. These results suggest that the ridge in pp collisions arises from the same or similar underlying physics as observed in p + Pb collisions, and that the dynamics responsible for the ridge has no strong root s dependence.
Çetin, Serkant Ali (Dogus Author)
Wed, 27 Apr 2016 00:00:00 GMThttp://hdl.handle.net/11376/31142016-04-27T00:00:00Z