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| DC 欄位 | 值 | 語言 |
|---|---|---|
| dc.contributor.advisor | 張寶棣(Pao-Ti Chang) | |
| dc.contributor.author | I-Huan Chiu | en |
| dc.contributor.author | 邱奕寰 | zh_TW |
| dc.date.accessioned | 2021-06-16T05:13:34Z | - |
| dc.date.available | 2014-08-21 | |
| dc.date.copyright | 2014-08-21 | |
| dc.date.issued | 2014 | |
| dc.date.submitted | 2014-08-18 | |
| dc.identifier.citation | [1] Combination of standard model Higgs boson searches and measurements of
the properties of the new boson with a mass near 125 GeV. [2] Single top quark production via SUSY-QCD FCNC couplings at the CERN LHC in the unconstrained MSSM. [3] J. A. Aguilar-Saavedra and B. M. Nobre, Phys. Lett. B 553, 2003. [4] D. Atwood, L. Reina and A. Soni, Phys. Rev. D 55, 1997. [5] H. J. He and C. P. Yuan, Phys. Rev. Lett. 83, 1999. [6] CMS Physics TDR: Volume I (PTDR1), Detector Performace and Software, 2007. [7] Johan Alwall, Michel Herquet, Fabio Maltoni, Olivier Mattelaer, Tim Stelzer, 2011. [8] hep-ph/0603175, LU TP 06-13, FERMILAB-PUB-06-052-CD-T, 2006. [9] Maryam Zeinali, Measurement of the Jet Energy Scale in the CMS experiment with the First LHC Proton Collisions, 2011 [10] J. A. Aguilar-Saavedra, Top flavor changing neutral coupling signals at a linear collider, Phys. Lett. B 502 (2001) 115, doi:10.1016/S0370-2693(01)00162- 9, arXiv:hep-ph/0012305. [11] G. Lu et al., Rare top quark decays t to cV in the topcolor assisted technicolor model, Phys. Rev. D 68 (2003) 015002, doi:10.1103/PhysRevD.68.015002, arXiv:hep-ph/0303122. [12] ATLAS Collaboration, A search for flavour changing neutral currents in top-quark decays in pp collision data collected with the ATLAS detector at sqrt(s) = 7 TeV. JHEP 1209 (2012) 139, doi:10.1007/JHEP09(2012)139, arXiv:1206.0257. [13] CMS Collaboration, The CMS experiment at the CERN LHC, JINST 03 (2008) S08004, doi:10.1088/1748-0221/3/08/S08004. [14] T. Han and J. L. Hewett, Top charm associated production in high-energy e+e collisions, Phys.Rev. D60 (1999) 074015, doi:10.1103/PhysRevD.60.074015, arXiv:hep-ph/9811237. [15] CMS Collaboration, Performance of b-jet identification in CMS, CMS Physics Analysisis Summary CMS-PAS-BTV-11-001, (2011). | |
| dc.identifier.uri | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/56033 | - |
| dc.description.abstract | 摘要
在標準模型中，頂夸克經由希格斯波色子以及魅夸克的衰變事件是被抑制的， 此事件的衰變比率被預測只有0.9x10-13，但在其他模型中預測此事件仍在可以 觀測的範圍。 在本實驗中，我們將藉由希格斯波色子衰變至兩個底夸克的過程，嘗試尋找頂 夸克衰變至希格斯波色子以及魅夸克的事件，而本實驗中所使用的數據為緊湊 緲子線圈在2012 年紀錄的質心能量為8TeV 之對撞數據，總通量為19.8fb-1。 經由在數據中所觀察到，滿足本次實驗選擇的背景以及訊號，可以計算出頂夸 克經由希格斯波色子以及魅夸克的衰變比率在95%的信心水準之下將不超過 0.98%。 我們期待能有更多的數據來證實本衰變事件的衰變比率。 關鍵字:大型強子對撞機，緊湊緲子線圈，希格斯波色子，味變中性流，頂夸 克，希格斯波色子衰變至底夸克對 | zh_TW |
| dc.description.abstract | Abstract
The Standard Model shows that branching fraction of flavor-changing neutral Higgs is 0.9 times 10−13 that means the FCNH process is be highly suppressed in SM. However, the two Higgs doublet model provides the branching fraction of FCNH can be 2.6 × 10−3, that is much larger than the one from Standard Model. This study is a search for the the branching fraction of t ! H + c, it’s interesting that might has the new physics different from Standard Model if the BR(t ! H + c) is larger than the one be predicted from SM. The branching fraction of higgs to b‾b channel is the highest one of all higgs decay channel which is about 60% where higgs mass is 125GeV, that the large efficiecy for signal is expectable. Therefore, this study is the searching for FCNH where higgs decay to b‾b channel with the integrated luminosity of about 19.8 fb−1 proton-proton collision data sample at a center-of-mass energy p s = 8TeV collected with the CMS detector. The observed upper limit calculted by the Higgs Combination Tool package with the Asymptotic method at 95% confidence level is 9.8 × 10−3 and the expected upper limit is 8.6 × 10−3 with the corresponding 1-¾ and 2-¾ bound which are [0.58%, 1.36%] and [0.42%, 2.16%]. The more powerful verification for the two Higgs doublet model can be provided with more data. | en |
| dc.description.provenance | Made available in DSpace on 2021-06-16T05:13:34Z (GMT). No. of bitstreams: 1 ntu-103-R00222064-1.pdf: 5133652 bytes, checksum: 79b51156b87bae5565139ae4bc01aed8 (MD5) Previous issue date: 2014 | en |
| dc.description.tableofcontents | Contents
1 Introduction 9 1.1 The Standard Model . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.1.1 Fermions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.1.2 Gauge Bosons . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.1.3 Higgs Boson . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.2 The Flavor-Changing Neutral Current in higgs decay . . . . . . . . . 10 2 Experimental Apparatus 12 2.1 The Large Hadron Collider . . . . . . . . . . . . . . . . . . . . . . . . 12 2.2 The Compact Muon Solenoid . . . . . . . . . . . . . . . . . . . . . . 14 2.2.1 Magnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.2.2 Muon system . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.2.3 Electromagnetic calorimeter . . . . . . . . . . . . . . . . . . . 15 2.2.4 Hadron calorimeter . . . . . . . . . . . . . . . . . . . . . . . . 17 2.2.5 Inner tracking system . . . . . . . . . . . . . . . . . . . . . . . 17 2.2.6 Trigger system . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3 Physical Object Reconstruction 20 3.1 Track Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3.2 Vertex Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3.3 Muon Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.4 Electron Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.5 Missing transverse energy MET . . . . . . . . . . . . . . . . . . . . . 23 3.6 Jet Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.7 b-jet Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 4 Data and Monte Carlo Samples 27 5 Event selection 29 5.1 High Level Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.2 Primary Vertex Selection . . . . . . . . . . . . . . . . . . . . . . . . . 30 5.3 Muon Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 5.4 Electron Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 5.5 Jet Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 3 6 Event Reweighting 36 6.1 Pile-up reweighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 6.2 Lepton ID efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 6.3 Trigger efficiency reweighting . . . . . . . . . . . . . . . . . . . . . . 37 6.4 Top pT efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 6.5 Combination Secondary Vertex reweighting . . . . . . . . . . . . . . . 38 7 Analysis Strategy 41 7.1 Best Candidate Choice . . . . . . . . . . . . . . . . . . . . . . . . . . 41 7.1.1 ¢A of t‾t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 7.1.2 Minimum A2 . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 7.1.3 Boosted Decision and Regression Trees . . . . . . . . . . . . . 42 7.2 Toolkit for Multivariate Data Analysis - Artificial Neural Networks . 43 8 Data/MC Comparison 48 9 Systematic Uncertainties 50 9.1 Luminosity Measurement . . . . . . . . . . . . . . . . . . . . . . . . . 50 9.2 Cross Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 9.3 Lepton Isolation and Selections . . . . . . . . . . . . . . . . . . . . . 50 9.4 Jet Energy Scale and Jet Energy Resolution . . . . . . . . . . . . . . 50 9.5 MET Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 9.6 Parton Distribution Function . . . . . . . . . . . . . . . . . . . . . . 51 9.7 Top pT reweighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 9.8 CSV reweighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 10 Limit calculation with fitting method 53 11 Conclusion 55 | |
| dc.language.iso | zh-TW | |
| dc.subject | 希格斯波色子衰變至底夸克對 | zh_TW |
| dc.subject | 大型強子對撞機 | zh_TW |
| dc.subject | 緊湊緲子線圈 | zh_TW |
| dc.subject | 希格斯波色子 | zh_TW |
| dc.subject | 味變中性流 | zh_TW |
| dc.subject | 頂夸克 | zh_TW |
| dc.subject | CMS | en |
| dc.subject | LHC | en |
| dc.subject | higgs to bb | en |
| dc.subject | top | en |
| dc.subject | FCNH | en |
| dc.subject | Higss | en |
| dc.title | 在8TeV質心能量的質子對撞實驗中尋找頂夸克衰變到希格斯波色子與魅夸克的事件 | zh_TW |
| dc.title | Search for top decays Charm and Higgs through flavor changing
neutral current process in CMS | en |
| dc.type | Thesis | |
| dc.date.schoolyear | 102-2 | |
| dc.description.degree | 碩士 | |
| dc.contributor.oralexamcommittee | 王名儒(Wang, Min-Zu),陳凱風(Chen, Kai-Feng),侯維恕(Hou, George Wei-Shu) | |
| dc.subject.keyword | 大型強子對撞機,緊湊緲子線圈,希格斯波色子,味變中性流,頂夸克,希格斯波色子衰變至底夸克對, | zh_TW |
| dc.subject.keyword | LHC,CMS,Higss,FCNH,top,higgs to bb, | en |
| dc.relation.page | 57 | |
| dc.rights.note | 有償授權 | |
| dc.date.accepted | 2014-08-18 | |
| dc.contributor.author-college | 理學院 | zh_TW |
| dc.contributor.author-dept | 物理研究所 | zh_TW |
| 顯示於系所單位： | 物理學系 | |
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