跳到主要內容

簡易檢索 / 詳目顯示

回結果列表
研究生： 吳俊億
Jun-Yi Wu
論文名稱： Search for Z'→Zh→llbb in pp Collisions at √s =8 TeV Using the CMS Detector at the LHC
指導教授： 余欣珊
Shin-Shan Yu
口試委員:
學位類別： 碩士
Master
系所名稱： 理學院 - 物理學系
Department of Physics
論文出版年： 2016
畢業學年度： 104
語文別： 英文
論文頁數： 80
中文關鍵詞： 高能物理 、大強子對撞機 、緊湊渺子線圈 、希格斯玻色子 、Z玻色子 、組合希格斯場模型
外文關鍵詞： High energy physics, LHC, CMS, Higgs boson, Z boson, composite Higgs model
相關次數： 點閱：11  下載：0 
分享至:
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報

    • 本論文係分析由大強子對撞機中的緊湊渺子線圈探測器所取得之對撞質子束中心能量為8 TeV、總時間積分之單位散射截面通量為19.7 /fb的數據，以尋找新理論模型預測之粒子衰變至Z玻色子與希格斯玻色子的信號。其使用b夸克標籤技術分析希格斯玻色子衰變後的b噴流來區隔信號與背景。結果已總結與報告在本論文的尾章。

    The result of a search for new particles decaying to Z and Higgs bosons with subsequent decay to a final state containing two leptons and two quarks, Z'→Zh→llbb, is reported. This analysis is based on the proton-proton collisions at √s = 8 TeV collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.7/fb. Subjet b-tagging techniques are exploited for separating the signal from the SM background when the boost of the Higgs causes the two b quarks to merge into the same jet reconstructed in the detector, and the exclusion limit result based on two dimension shape method is presented.

    1 Introduction and Theory Overview 1 1.1 Introduction................................1 1.2 Theory Overview.............................2 1.2.1 Heavy Vector Triplet Model...................2 1.2.2 Basic Phenomenology.......................3 1.2.3 Explicit Models..........................8 2 The LHC and the CMSDetector 11 2.1 Large Hadron Collider..........................11 2.2 Compact Muon Solenoid.........................13 2.2.1 Tracker..............................15 2.2.2 ECAL...............................16 2.2.3 HCAL...............................17 2.2.4 Muon Chamber..........................19 2.2.5 Trigger System..........................20 3 Analysis Procedures 22 3.1 Monte Carlo Samples and Datasets...................22 3.1.1 Signal MC.............................22 3.1.2 Background MC..........................24 3.1.3 Data Samples...........................24 3.2 Trigger...................................25 3.3 Physics Objects..............................26 3.3.1 Muon...............................26 3.3.2 Electron..............................29 3.3.3 Jet.................................33 3.3.4 Jet Grooming Algorithms....................35 3.3.5 b-tagging.............................37 3.4 Pile-up reweighting............................40 3.5 Event and Objectselection........................41 3.5.1 Lepton Requirements.......................41 3.5.2 Jet Requirement.........................41 3.5.3 Z boson Requirement.......................42 3.6 Data-MC comparison...........................44 3.7 Background Estimation..........................49 3.7.1 α ratio method..........................49 3.8 Signal Yields...............................50 3.8.1 signal effciency..........................50 3.8.2 The mZh spectrum........................51 3.8.3 The CSV distribution.......................53 3.9 Systematic uncertainties.........................56 4 Results and conclusion 60 4.1 Exclusion limit results..........................60 4.1.1 Counting result..........................60 4.1.2 1D shape result..........................61 4.1.3 2D shape result..........................61 4.2 Conclusion.................................61

    [1] CMS Collaboration. Jet mass in dijet and vector boson plus jet events. CMS Physics Analysis Summary CMS-PAS-SMP-12-019, CMS,2012.
    [2] CMS Collaboration. Identifcation of b-quarks jets with the CMS experiment. JINST, 8:P04013,2013.
    [3] ATLAS Collaboration. Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC. Phy. Lett.B, 716:1, 2012.
    [4] CMS Collaboration. Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC. Phy. Lett.B, 716:30,2012.
    et al.

    QR CODE
    :::