Tek Lepton Kanalında Standart Model Ardalan Analizi

Protonlar temel parçacık olmadıkları için, proton-proton çarpışmalarında büyük bir ardalan üretirler. Dolayısıyla, süpersimetri arayışlarında ana problem, süpersimetrik sinyalleri bu Standart Model ardalanından ayırmaktır. Bu nedenle, kapsamlı bir ardalan analizi, süpersimetri arayışları yönünde bilgi edinebilmek için önemli hale gelir. Tek lepton kanalı, Standart Model ardalanının elde edildiği etkin süreçlerden biridir. Bu çalışmada, çeşitli olaylardan oluşan ardalan üretilmiş, homojen ve temiz bir ardalan oluşabilmesi için temel seçimler ve kesimler uygulanmıştır. Öte yandan, dedektörde iz bırakmadan kaçabilen parçacıkları tespit edebilmek için, kayıp enine enerjinin büyüklüğü ve tüm enine momentumlarım skaler toplamı oldukça önemlidir. Bu nedenle, gerekli tüm histogramlar çizilmiştir. Ardalan, büyük ölçüde W-bozonları + jetleri ve top kuark-antikuark + jetlerinden oluşmakla birlikte, neredeyse tüm enerji bölgelerinde en fazla katkı, W+jetlerinden gelmektedir. Ancak çok sayıda jet üreten çarpışmalar için top kuark-antikuark + jetleri daha baskın hale gelmektedir. Çalışmanın son adımı ise, potansiyel süpersimetri sinyallerinin izolasyonu için ek seçimler ve kesimlerin uygulanmasıdır.

Anahtar Kelimeler:

Süpersimetri, Standart Model, Tek lepton kanalı, Analiz

Standard Model Background Analysis for Single Lepton Channel

Since protons are not fundamental particles, they produce very large backgrounds in proton-proton collisions. Therefore, in supersymmetry searches, the main challenge is to differentiate supersymmetric signals from Standard Model background. Hence, extensive background analysis becomes an important probe to obtain information in the direction of supersymmetry searches. Among the variety of signatures in this direction, single lepton channel is one of the effective processes in which Standard Model background is obtained. In this work, starting from the generation of background emerging from various events, basic selections and cuts have been applied to obtain a homogenous and a clean sample. On the other hand, the magnitude of missing transverse energy and scalar sum of all transverse momentums are crucial to detect particles that can escape without leaving trace in the detector. Therefore, all necessary histograms have been plotted. Emerging the leading backgrounds from W-bosons + jets and top quark-antiquark + jets events, almost all energy regions, it is seen that W+jets have greater contribution to background. However, for the collisions that produce high number of jets top quark-antiquark + jets become more dominant. Final step of the work is the application of additional selections and cuts for the isolation of potential supersymmetry signals.

Keywords:

Supersymmetry, Standart Model, Single lepton channel, Analysis,

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