Browsing by Author "Sultansoy, Saleh"

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    Measurement of the inclusive cross-section for the production of jets in association with a Z boson in proton–proton collisions at 8 TeV using the ATLAS detector
    (2019) Çakır, Orhan; Duran Yıldız, Hatice; Kuday, Sinan; Sultansoy, Saleh; Türk Çakır, İlkay; Fen Fakültesi
    The inclusive cross-section for jet production in association with a Z boson decaying into an electron–positron pair is measured as a function of the transverse momentum and the absolute rapidity of jets using 19.9 fb- 1 of s=8 TeV proton–proton collision data collected with the ATLAS detector at the Large Hadron Collider. The measured Z+ jets cross-section is unfolded to the particle level. The cross-section is compared with state-of-the-art Standard Model calculations, including the next-to-leading-order and next-to-next-to-leading-order perturbative QCD calculations, corrected for non-perturbative and QED radiation effects. The results of the measurements cover final-state jets with transverse momenta up to 1 TeV, and show good agreement with fixed-order calculations.
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    Renk sekizlisi elektron'un (e8) TeV enerji ölçekli çarpıştırıcılarda aranması
    (Fen Bilimleri Enstitüsü, 2019) Kaya, Ümit; Türköz, Şemsettin; Sultansoy, Saleh; Fen Fakültesi
    Bu tezde, maddenin muhtemel yeni yapı düzeyi olduğu düşünülen preon modelleri incelenmiş ve yeni bir minimal preon modeli önerilmiştir. Mevcut ve gelecekte kurulması düşünülen çarpıştırıcıların preon modellerinin öngördüğü parçacıklardan biri olan renk sekizlisi elektronu araştırma potansiyelleri belirlenmiştir. Çalışma sırasında FCC ve SppC temelli enerji öncephesi ep çarpıştırıcıları önerilmiş ve ana parametreleri irdelenmiştir. Ayrıca IceCube işbirliği tarafından 2012-2013 yılları arasında gözlemlenen PeV enerjili nötrino olaylarının, yine preon modellerinin öngördüğü parçacıklardan olan renk sekizlisi nötrinolar olarak yorumlanmıştır. In this thesis, preon models which are thought to be possible new building level of the matter has been reviewed and a new minimal preon model has been proposed. Then the search potential of existing and future colliders for color octet electron, which is one of the particles predicted by the preon models, has been determined. During the study, FCC and SppC based energy frontier ep collider have been proposed and their main parameters have been evaluated.In addition, the PeV energy neutrino events, observed between the years 2012-2013 by IceCube collaboration, have been interpreted as color octet neutrino which is also predicted by the preon models.
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    Searches for scalar leptoquarks and differential cross-sectionmeasurements in dilepton–dijet events in proton–proton collisionsat a centre-of-mass energy of√s= 13 TeV with the ATLASexperiment
    (2019) Çakır, Orhan; Duran Yıldız, Hatice; Kuday, Sinan; Sultansoy, Saleh; Türk Çakır, İlkay; Fen Fakültesi
    Searches for scalar leptoquarks pair-produced in proton–proton collisions at s=13 TeV at the Large Hadron Collider are performed by the ATLAS experiment. A data set corresponding to an integrated luminosity of 36.1 fb- 1 is used. Final states containing two electrons or two muons and two or more jets are studied, as are states with one electron or muon, missing transverse momentum and two or more jets. No statistically significant excess above the Standard Model expectation is observed. The observed and expected lower limits on the leptoquark mass at 95% confidence level extend up to 1.29 TeV and 1.23 TeV for first- and second-generation leptoquarks, respectively, as postulated in the minimal Buchmüller–Rückl–Wyler model, assuming a branching ratio into a charged lepton and a quark of 50%. In addition, measurements of particle-level fiducial and differential cross sections are presented for the Z→ ee, Z→ μμ and tt¯ processes in several regions related to the search control regions. Predictions from a range of generators are compared with the measurements, and good agreement is seen for many of the observables. However, the predictions for the Z→ ℓℓ measurements in observables sensitive to jet energies disagree with the data.