在緊湊渺子線圈探測器透過隱形產物衰變通道量測弱電作用生成之Z 玻色子與光子伴隨兩束噴流於質心能量13 兆電子福特的質子-質子對撞過程

Abstract

本篇論文陳述測量經由弱電作用生成之Z 玻色子與光子且Z 玻色子衰變成微中子-反微中子對的方法。此測量方法應用於利用緊湊秒子線圈在2017-2018 年，大型強子對撞機第二期運轉期間收集的＂缺失橫向能量數據集＂。數據全數經由質子-質子於對撞質心能量13 兆電子福特中生成，加總積分亮度101.24 fb−1。目標訊號是透過向量玻色子散射產生，因此，終態特徵是有兩個高能量噴流極前向射出，且兩個噴流有相當大的贗快度夾角。相對於前向，較中心生成的Z 玻色子與光子主要由探測器筒狀區域偵測。然而，由Z 衰變產生的微中子-反微中子對是以缺失橫向能量形式被量測而非粒子物件形式。所有背景事件貢獻源於標準例子模型已知過程皆由蒙地卡羅法產生模擬數據樣本。無法被模擬或模擬效果不佳的背景事件將採用真實數據估算結果，因真實數據已考量探測器效應。基準體積中橫截面量利用＂缺失橫向能量數據集＂成功量測，在領頭項精準度測得0.69±0.12fb。

The thesis presents the approach for EW Z(νν)γ+2jets measurement with the MET dataset collected with the CMS detector during the LHC Collider Run2 in 2017-2018, with a proton-proton collision at √s = 13 TeV and the integrated luminosity corresponds to a total of 101.24 fb−1. The target signal is procured via the vector boson scattering process, therefore, the final state features two energetic jets shooting forwardly with a large separation in the pseudorapidity. The photon and Z boson are generated centrally and mostly detected in the barrel region of the CMS detector. However, the neutrino-antineutrino pair which decays from the Z boson appears as a quantity of missing energy instead of particle objects in the detector. All background contributions from standard model benchmark processes sharing the same final state signature are estimated by Monte Carlo simulated samples. Non-simulated or not well-simulated backgrounds are estimated from real data including all detector effects. The fiducial cross-section measurement for this process only succeded in the MET dataset, with measured 0.69±0.12 fb at the accuracy of the leading order.