Yazar "Dilsiz, Kamuran" seçeneğine göre listele

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    A phenomenological calculation for W+W- diboson production for the Large Hadron Collider and Future Circular Collider
    (Tubitak Scientific & Technological Research Council Turkey, 2018) Dilsiz, Kamuran; Ogul, Hasan
    The Large Hadron Collider (LHC) at CERN has been designed to collide beams of protons at 7, 8, 13, and 14 TeV center-of-mass energies and a new hadron collider called the Future Circular Collider (FCC), which is larger and more energetic than the LHC, is being planned for the near future. The maximum planned energy for FCC is 100 TeV center-of-mass energy. In this regard, we present the leading order and next-to-leading order cross-section predictions of two simultaneously produced opposite-sign W bosons at 7, 8, 13, 14, and 100 TeV center-of-mass energies by using the MCFM MC generator. The results are obtained by CT14, MMHT2014, and MSTW2008 parton distribution functions. Finally, the advantage of increasing collision energy at hadron colliders is discussed by comparing the amount of data recorded at different center-of-mass energies for the pp -> W+W- process.
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    Cross Section Prediction for Inclusive Production of Z Boson in pp Collisions at √s=14TeV: A Study of Systematic Uncertainty due to Scale Dependence
    (Hindawi Ltd, 2017) Ogul, Hasan; Dilsiz, Kamuran
    Prediction of Z -> l(+)l(-) production cross section (where l(+/-) = e(+/-) mu(+/-)) in proton-proton collisions at root s = 14TeV is estimated up to next-to-next-to-leading order (NNLO) in perturbative QCD including next-to-leading order (NLO) electroweak (EW) corrections. The total inclusive Z boson production cross section times leptonic branching ratio, within 116 GeV, is predicted using NNLO HERAPDF2.0 at NNLO QCD and NLO EW as.. Tot the invariant mass window 66 < m(u) < 116 GeV, is predicted using NNLO HERAPDF2.0 at NNLO QCD and NLO EW as sigma(Tot)(z) = 2111.69(-26.92)(+26.31) (PDF) +/- 11 (alpha(s)) +/- 17 (scale(-30.98)(+57.41)) (parameterization and model). Theoretical prediction of the fiducial cross section is further computed with the latest modern PDF models (CT14, MMHT2014, NNPDF3.0, HERAPDF2.0, and ABM12) at NNLO for QCD and NLO for EW. The central values of the predictions are based on DYNNLO 1.5 program and the uncertainties are extracted using FEWZ 3.1 program. In addition, the cross section is also calculated as functions of mu(R) and mu(F) scales. The choice of mu(R) and mu(F) for scale variation uncertainty is further discussed in detail.
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    Estimation of neutron and gamma-ray attenuation characteristics of some ferrites: Geant4, FLUKA and WinXCom studies
    (Pergamon-Elsevier Science Ltd, 2023) V. More, Chaitali; Akman, Ferdi; Dilsiz, Kamuran; Ogul, Hasan; Pawar, Pravina P.
    Ferrites are ceramic oxide materials consisting of mainly iron oxide and they have become massively important materials commercially and technologically, having a multitude of uses and applications. The protection against neutron-gamma mixed radiation is crucial in several nuclear applications. From this standpoint, mass attenuation coefficient, radiation protection efficiency and transmission factor of some ferrites namely barium, strontium, manganese, copper and cadmium ferrite has been computed using Geant4 and FLUKA simulations. Based on the simulated mass attenuation coefficient, other significant parameters such as linear attenuation coefficient, effective atomic and electron number, conductivity, half value layer, and mean free path were calculated for the selected ferrite materials. The validation of Monte Carlo geometry has been provided by comparing the mass attenuation coefficient results with standard WinXCom data. Gamma ray exposure buildup factors were computed using geometric progression fitting formula for the chosen ferrites in the energy range 0.015-15 MeV at penetration depths up to 40 mfp. The findings of the present work reveal that among the studied ferrites, barium ferrite and copper ferrite possess superior gamma ray and fast neutron attenuation capability, respectively. The present work provides a comprehensive investigation of the selected iron oxides in the field of neutron and gamma ray.
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    Evaluation of CdS doped polyester composites regarding gamma and neutron shielding properties
    (Pergamon-Elsevier Science Ltd, 2021) Dilsiz, Kamuran; Ogul, Hasan; Akman, Ferdi; Agar, Osman; Kacal, Mustafa Recep; Polat, Hasan; Dursun, Inan
    In this study, CdS doped polyester composites were produced at different weight ratios, and the impact of dopant amount on gamma and neutron shielding characteristics of a new composite material were further evaluated: the composite matrix was doped at 5%, 10%, 15% and 20% CdS weight ratios of the prepared composite. Then, the produced polyester materials have been characterized using a scanning electron microscope (SEM) and X-ray diffraction (XRD) patterns. Following the structure characterization, the prepared composites were tested using one gamma spectrometer system based HPGe detector with help of Na-22, Mn-54, Co-57, Co-60, Ba-133, Cs-137, Eu-152 and Am-241 radioactive point-isotropic sources in order to perform the evaluation in a wide energy range of gamma. The obtained results were compared to the results of Geant4 and WinXCOM simulation codes. On the last step of the presented work, the neutron removal cross sections of produced polyester composites were calculated using partial density of elements and their cross sections, and then, neutron shielding characteristics of the prepared samples were determined with help of Geant4 simulation toolkit. Both tested and simulated results of gamma shielding evaluation showed good agreement, and, for all considered photon energies, mass attenuation coefficient (mu/p) values of CdS (20%) were always found to be greater than the mu/p values of other samples (5%, 10%, 15%). The results for neutron shielding showed that neutron transmission was decreasing with the increase of CdS in the material. In short, having higher mu/p values and lower neutron transmission shows that increasing the amount of CdS in the sample causes the higher radiation shielding property for both gamma and neutron.
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    Forward-backward asymmetry of Drell-Yan lepton pairs at 14 TeV center-of-mass energy
    (Tubitak Scientific & Technological Research Council Turkey, 2018) Dilsiz, Kamuran; Ogul, Hasan
    In this paper, fiducial cross-sections of lepton pairs with opposite charge via Z -> l(+)l(-) (l(+/-) = mu(+/-), e(+/-)) are calculated at a center-of-mass energy of 14 TeV by applying different transverse momentum selections to evaluate their impact on the production cross-section as well as the differential cross-section of Z bosons in terms of lepton pseudorapidity. The predictions are computed by next-to-next-to-leading order quantum chromodynamics including next-to-leading order electroweak corrections. Forward-backward asymmetry prediction for the Drell-Yan production in proton-proton collision is further calculated at 14 TeV using HERAPDF2.0, MMHT2014, NNPDF3.1, and CT14 parton distribution function models. Then 14 TeV QCD predictions of forward-backward asymmetry are presented as a function of dilepton mass for four different Z boson rapidity regions.
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    Gamma radiation shielding performance of CuxAg(1-x)-yalloys: Experimental, theoretical and simulation results
    (Pergamon-Elsevier Science Ltd, 2022) Turhan, Mehmet Fatih; Akman, Ferdi; Taser, Ahmet; Dilsiz, Kamuran; Ogul, Hasan; Kacal, Mustafa Recep; Agar, Osman
    Different types of photon shielding parameters such as total mass attenuation coefficient (mu/p), linear attenuation coefficients (mu), half value layers (HVL), mean free paths (MFP), effective atomic numbers (Z(Eff)), energy absorption build-up factors (EABF), exposure build-up factors (EBF) and kerma relative to air were investigated for the fabricated Cu-Ag based alloys. The considered parameters were measured through gamma spectrometer equipped with HPGe detector in order to obtain the experimental attenuation coefficients and other related parameters at various photon energy in the energy range 59.5-1332.5 keV. The measured mu/rho values were confirmed with WinXCOM database results. FLUKA and GEANT4 simulation codes were used to examine the compatibility of the experimental and WinXCOM database results with these simulation codes. The exposure buildup factors of the alloy samples were estimated with help of Geometric Progression fitting formula over photon energy 0.015-15 MeV up to 40 mfp penetration depth. The results revealed that the exhibited effectiveness of Cu0.2Ag0.8 alloys against high energetic photon radiations had a good performance than that of alternative absorbers such conventional concretes, glasses and some alloys. The results of the present survey can be quite useful for possible applications of such materials, especially in nuclear laboratory and reactor core design for preference of effective photon shielding materials.
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    High Order QCD Predictions for Inclusive Production of W Bosons in pp Collisions at √s=13 TeV
    (Hindawi Ltd, 2016) Ogul, Hasan; Dilsiz, Kamuran; Tiras, Emrah; Tan, Ping; Onel, Yasar; Nachtman, Jane
    Predictions of fiducial cross sections, differential cross sections, and lepton charge asymmetry are presented for the production of W-+/- bosons with leptonic decay up to next-to-next-to-leading order (NNLO) in perturbative QCD. Differential cross sections of W-+/- bosons and W boson lepton charge asymmetry are computed as a function of lepton pseudorapidity for a defined fiducial region in pp collisions at root s = 13TeV. Numerical results of fiducial W-+/- cross section predictions are presented with the latest modern PDF models at next-to-leading order (NLO) and NNLO. It is found that the CT14 and NNPDF 3.0 predictions with NNLO QCD corrections are about 4% higher than the NLO CT14 and NNPDF 3.0 predictions while MMHT 2014 predictions with NLO QCD corrections are smaller than its NNLO QCD predictions by approximately 6%. In addition, the NNLO QCD corrections reduce the scale variation uncertainty on the cross section by a factor of 3.5. The prediction of central values and considered uncertainties are obtained using FEWZ 3.1 program.
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    Proton Proton Çarpışmaları Sonucu Aynı Anda Üretilen Higgs Ve Vektör Bozonları?Nın 14, 27 Ve 100 Tev Kütle Merkez Enerjilerindeki Yüksek Mertebeli Kuantum Renk Dinamiği (Qcd) Tahminleri.
    (2023) Dilsiz, Kamuran; Tiras, Emrah; Bat, Ayse; Ogul, Hasan; Yılmaz, Meryem
    Bu çalışmada gelecekte Avrupa Nükleer Araştırmalar Merkezi (CERN)'nde kurulması ön görülen HL-LHC, HE-LHC ve FCC gibi yüksek enerjili hızlandırıcılarda incelenmesi planlanan Higgs sinyali'nin elde edilmesini kolaylaştıracak Higgs bozonunun bir vektör bozonu ile üretiminin yüksek mertebeli QCD tesir kesitleri hesaplanmıştır. Hesaplamalar yapılırken proton çarpışmaları sonucu eş zamanlı oluşan W/Z ve Higgs üretim kanallarının birçok dallanma durumu dikkate alınmıştır. Bu bağlamda, 14, 27 ve 100 TeV kütle merkez enerjilerinde WH ve ZH üretim kanallarının dallanma durumları hesaba katılarak leading order (LO), next-to-leading order (NLO) ve next-to-NLO (NNLO) QCD tesir kesitleri hesaplanmıştır. Artan kütle merkez enerjisi ile tesir kesitinin artmasının yanı sıra, aynı enerjide yüksek mertebeli NLO ve NNLO QCD tesir kesitlerinin en düşük mertebe olan LO mertebesine kıyasla arttığı gözlemlenmiştir. Hali hazırda CERN Büyük Hadron Çarpıştırıcısı deneyleri olan CMS ve ATLAS guruplarının kullanmış oldukları eşik değerlerine yakın değerler seçilerek bir simülasyon çerçevesi oluşturulmuş, dört farklı parton dağılım fonksiyonu (PDF) ve dokuz farklı renormalizasyon ve faktörizasyon değeri kullanılarak K faktör hesaplamaları yapılmıştır. Hesaplanan K faktör değerlerinin çok küçük olması ile oluşturulan simülasyon çerçevesinin güvenilirliği test edilmiştir. Ayrıca, LO, NLO ve NNLO QCD değerlerinin PDF, scale ve alfa_S hata payları hesaplanarak scale ve toplam hata paylarının çok yüksek olduğu LO mertebesine kıyasla NLO ve NNLO QCD düzeltmelerinde çok düşük hata payları tespit edilmiştir. Böylece, yüksek mertebeli hesaplamaların ekstra partonik süreçlerin ilave edilmesiyle daha doğru tesir kesiti sonucunu vermelerinin yanı sıra ilgili üretim kanallarında düşük hata paylarına sahip oldukları tespit edilmiştir. LHC enerjilerinde (7,8,13 ve 14 TeV), HE-LHC enerjisinde (27 TeV) ve FCC-hh enerjisinde (100 TeV) hesaplanan en yüksek QCD düzeltmesi NNLO dikkate alınarak 7 TeV kütle merkez enerjisindeki veri ile elde edilen istatistiği daha yüksek enerjilerde elde edebilmek için ihtiyaç duyulan veri miktarı hesaplanmıştır. Sonuç olarak yüksek enerjilerde daha düşük veri ile düşük enerjilerdeki olay sayısının elde edilebileceği tespit edilmiştir. Özellikle, FCC-hh?nin enerjisi olan 100 TeV?de 7, 8 ve 13 TeV kütle merkez enerjilerindeki veri miktarından yaklaşık 10-15 kat daha az veri ile aynı istatistiğin elde edilebileceği görülmüştür.
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    QCD predictions for simultaneously produced Higgs and vector bosons at s=13, 14, 27 and 100 TeV with a comprehensive study of systematic uncertainty and charge asymmetry
    (Springer, 2025) Dilsiz, Kamuran; Tiras, Emrah; Yilmaz, Meryem; Ogul, Hasan
    A comprehensive study of high-order QCD cross-section for the Higgs boson that is simultaneously produced with a vector boson is presented at s = 13, 14, 27 and 100 TeV in this manuscript. The simultaneous Higgs production with a vector boson facilitates the investigation of the Higgs signal. In the calculations, three different branching states of the Higgs (tau-tau+, bb, gamma gamma) and vector bosons [W +/-(e +/-nu(nu)),Z(e-e+)] were taken into account. Here, leading order (LO), next-to-leading order (NLO), and next-to-NLO (NNLO) QCD cross-sections were calculated for these branching states. A simulation framework was built for the calculations at the TRUBA high-performance grid computing center. Then, the threshold values (selection cuts) close to the values used by the CMS and ATLAS Collaborations were selected and used on several parameters such as invariant mass, transverse momentum ( pT), pseudorapidity (eta), etc. In addition, NNPDF3.1 parton distribution functions (PDF) were used during the calculation. The results showed that the numerical value of the QCD prediction increases at NLO and NNLO as compared to the LO predictions. In addition to the higher-orders, the cross-section value increases as the center-of-mass energy increases. In addition to the QCD predictions, PDF, scale, and aS uncertainties of theQCD-predictions were also calculated to test the reliability of the highorder QCDs. The results showed that total and scale uncertainties decrease as the QCD order increases. In addition, it was found that LO total and scale uncertainties increase significantly as the center-of-mass energy increases, while NLO and NNLO scale and total uncertainties remain almost constant or show a negligible increase as the center-of-mass energy increases. This indicates that high-order QCDs not only provide more accurate results by the addition of extra partonic diagrams but also provide lower uncertainties in the relevant production channels. Furthermore, the required data that provides the exact statistics for physicsmeasurements of simultaneously produced Higgs and vector bosons as the data at 13 TeV were predicted at s = 14, 27, and 100 TeV. As a result, we found that the same statistics for accurate physics measurements can be obtained at s = 14, 27, and 100 TeV with approximately 1.1, 2.0, and 6.5 times less data than the amount of data at s = 13 TeV, respectively. In the last section of this study, Wboson charge asymmetry was computed at NNLO QCD. The lowest charge asymmetry between W + and W - was obtained at the WH(tau-tau+) decay channel and the highest charge asymmetry results were obtained at the WH(bb) decay channel.
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    Secondary Emission Calorimetry -2
    (MDPI, 2022) Bilki, Burak; Dilsiz, Kamuran; Ogul, Hasan; Onel, Yasar; Southwick, David; Tiras, Emrah; Wetzel, James
    Electromagnetic calorimetry in high-radiation environments, e.g., forward regions of lepton and hadron collider detectors, is quite challenging. Although total absorption crystal calorimeters have superior performance as electromagnetic calorimeters, the availability and the cost of the radiation-hard crystals are the limiting factors as radiation-tolerant implementations. Sampling calorimeters utilizing silicon sensors as the active media are also favorable in terms of performance but are challenged by high-radiation environments. In order to provide a solution for such implementations, we developed a radiation-hard, fast and cost-effective technique, secondary emission calorimetry, and tested prototype secondary emission sensors in test beams. In a secondary emission detector module, secondary emission electrons are generated from a cathode when charged hadron or electromagnetic shower particles penetrate the secondary emission sampling module placed between absorber materials. The generated secondary emission electrons are then multiplied in a similar way as the photoelectrons in photomultiplier tubes. Here, we report on the principles of secondary emission calorimetry and the results from the beam tests performed at Fermilab Test Beam Facility as well as the Monte Carlo simulations of projected, large-scale secondary emission electromagnetic calorimeters. © 2022 by the authors.