Skaler Bozon Aracılığıyla Üst Kuarkın Çeşni Değiştiren Yüksüz Akım Etkileşmelerinin Araştırılması

Abstract

Today, high energy physics has entered a new phase with the discovery of the Higgs boson within the framework of the Standard Model (SM). At this stage, scientists focused on the unresolved problems of the model that has been put forward to date. The exact solutions to the problems here are indisputably in need of empirical verification. On the other hand, the results from the Large Hadron Collider (LHC) cannot confirm any post-SM model proposed for solving the problems of the SM. This situation pushes researchers to search for new physics in the data to be obtained from experiments to be carried out in higher energy accelerators. In this study, which is the subject of the thesis, the observation potential of flavor-changing no-charge current (FCNC) type interactions in new colliders was investigated within the framework of effective field theory and using simulation method, in order to find answers to the questions left unanswered by SM. In this direction, the anomalous interactions of the top quark, which are currently frequently studied, were investigated. Testing the predictions obtained from these studies with experiments is undoubtedly the most crucial part of the work. Experimental measurements of such interactions are very sensitive and predictions are easily testable. Therefore, it is possible to open the door to possible new physics discoveries or exclusions on interaction constants with this type of studies that will also guide experiments. In this context, in the thesis, FCNC interaction of top quark and Higgs boson was first investigated in the lepton channel of the same sign in the High-Irradiance Large Hadron Collider (HL-LHC) and it was concluded that the channel is suitable for exclusion. The interaction constant for the exclusion scenario is \eta_{q}=0.04 and the corresponding branching ratio is 3.048\times10^{-4}, in line with HL-LHC expectations. In a later search for FCC-hh, \eta_{q}=0.0059 for the discovery scenario and the corresponding branching ratio is 1.32\times10^{-5} and \eta_{q}=0.0027 for the exclusion scenario corresponding branching ratio was found as 2.78\times10^{-6}.