本篇論文的研究主題為尋找具有長生命週期新粒子的物理模型所預測
的暗物質。在此模型中，一對正反夸克交互作用會產生一個??波色子與 ??′波色子，??波色子會衰變成一對正反電子，而 ??′波色子會產生一對具有生命週期的新粒子??2，??2會各自衰變成暗物質??1與一對d夸克，並在偵測器中被偵測為displaced噴流。本分析所使用的資料來自大型強子對撞機緊湊緲子線圈偵測器所收集的質子-質子對撞實驗，其質心能量為13TeV，且積分光度為35.9?????1，為2016 Run II 蒙地卡羅事件。本研究首先利用三維軌跡變數研究不同質量點與生命週期對於噴流變量??3?? 的影響，進而進行最佳化的變量篩選，最後使用假訊息率的方法進行背景物理的量測與預估。;A search for dark matter produced in association with mono-Z(ee), predicted by an extended theoretical model. In this model, a pair of interacting quarks produce a Z boson and a Z′ boson. The Z boson decays into a pair of electrons channel, while the Z′ boson produces a pair of new particles X2 with a lifetime. Each X2 further decays to a stable dark matter \chi_1 and a pair of d quarks are detected as displaced AK4 jets in the detector. The analysis data used in this study were collected from proton-proton collision experiments conducted vat center-of-mass energy √s = 13 TeV, corresponding to an integrated luminosity of 35.9 fb-1, using the CMS detector, specifically the 2016 Run II Monte Carlo events. This study first explores the effects of different mass points and lifetimes on the jet variable alpha_{3D} using three-dimensional track variables, then optimization of the variable selection and using a fake rate method to measure and estimate the background physics.
