https://scholars.lib.ntu.edu.tw/handle/123456789/31963
DC 欄位 | 值 | 語言 |
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dc.contributor | 張寶棣 | en |
dc.contributor | 臺灣大學:物理研究所 | zh_TW |
dc.contributor.author | 雷永吉 | zh |
dc.contributor.author | Lei, Yeong-Jyi | en |
dc.creator | 雷永吉 | zh |
dc.creator | Lei, Yeong-Jyi | en |
dc.date | 2006 | en |
dc.date.accessioned | 2007-11-26T09:15:55Z | - |
dc.date.accessioned | 2018-06-28T09:38:25Z | - |
dc.date.available | 2007-11-26T09:15:55Z | - |
dc.date.available | 2018-06-28T09:38:25Z | - |
dc.date.issued | 2006 | - |
dc.identifier | en-US | en |
dc.identifier.uri | http://ntur.lib.ntu.edu.tw//handle/246246/54486 | - |
dc.description.abstract | The CMS (Compact Muon Solenoid) experiment is located at the LHC (Large Hardon Collider) proton-proton collider in CERN. The center of mass energy of the proton-proton collider is 14 TeV. The experiment plans to start taking data at early 2008. Besides the pair top quark production observed by CDF (The Collider Detector at Fermilab) and D0 (DZero), the Standard Model also allows single top quark production which we expect to observe in the LHC with the CMS detector. The single top is produced by electroweak interaction and this gives us a window to directly measure the CKM (Cabbibo-Kobayashi-Maskawa) matrix element |Vtb| since the production cross section is proportional to jVtbj2. Assuming three quark generations or unitarity of the CKM matrix can imply |Vtb|~1. However, if the fourth generation exists, |Vtb| can be any number smaller then 1. There are three modes of single top production: (1) t-channel, (2) s-channel, and (3)W associated production or tW. Based on Monte Carlo simulation, a study of cross section and significance of tW production in the CMS experiment is presented in this thesis. | en |
dc.description.tableofcontents | Contents 1 Introduction 1 2 The LHC and the CMS Experiment 7 2.1 The Large Hadron Collider . . . . . . . . . . . . . . . . . . . . 7 2.2 CMS detector . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2.1 Magnet . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2.2 Inner tracking system . . . . . . . . . . . . . . . . . . . 12 2.2.3 Electromagnetic calorimeter . . . . . . . . . . . . . . . 14 2.2.4 Hadron calorimeter . . . . . . . . . . . . . . . . . . . . 15 2.2.5 Muon chambers . . . . . . . . . . . . . . . . . . . . . . 16 2.2.6 The trigger system . . . . . . . . . . . . . . . . . . . . 17 3 Reconstruction 19 3.1 Track reconstruction . . . . . . . . . . . . . . . . . . . . . . . 19 3.2 Vertex reconstruction . . . . . . . . . . . . . . . . . . . . . . . 20 3.3 Muon reconstruction . . . . . . . . . . . . . . . . . . . . . . . 20 3.4 Electron reconstruction . . . . . . . . . . . . . . . . . . . . . . 21 3.5 Jet reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.6 b tagging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 5 6 CONTENTS 4 Simulation 27 4.1 Events generation . . . . . . . . . . . . . . . . . . . . . . . . . 27 4.2 Detector simulation . . . . . . . . . . . . . . . . . . . . . . . . 27 4.3 Adding pile-up events . . . . . . . . . . . . . . . . . . . . . . . 28 4.4 Digitization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 4.5 Fast Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . 28 4.5.1 Pile-up treatments . . . . . . . . . . . . . . . . . . . . 28 4.5.2 Modification on FAMOS . . . . . . . . . . . . . . . . . 29 4.6 Event reconstruction . . . . . . . . . . . . . . . . . . . . . . . 29 5 Monte Carlo Samples 31 5.1 Backgrounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 5.2 Monte Carlo production . . . . . . . . . . . . . . . . . . . . . 33 6 Extra Jet Reduction 35 6.1 Study with single muon sample . . . . . . . . . . . . . . . . . 35 6.2 Study with tW semi-leptonic sample . . . . . . . . . . . . . . 38 6.3 Pile-up jets reduction . . . . . . . . . . . . . . . . . . . . . . . 39 6.4 Extra jets reduction . . . . . . . . . . . . . . . . . . . . . . . . 42 7 Trigger and Event Selection 47 7.1 Triggers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 7.2 Lepton quality requirement . . . . . . . . . . . . . . . . . . . 48 7.3 Jet quality requirement . . . . . . . . . . . . . . . . . . . . . . 49 7.4 b tagging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 7.5 Isolation cuts . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 7.6 Kinematic cuts . . . . . . . . . . . . . . . . . . . . . . . . . . 50 CONTENTS 7 7.7 Event reconstruction . . . . . . . . . . . . . . . . . . . . . . . 50 7.7.1 The hadronic decayed W . . . . . . . . . . . . . . . . . 50 7.7.2 The leptonic decayed W . . . . . . . . . . . . . . . . . 51 7.7.3 The top quark reconstruction . . . . . . . . . . . . . . 52 7.8 The signal region . . . . . . . . . . . . . . . . . . . . . . . . . 53 7.9 Estimation of efficiencies . . . . . . . . . . . . . . . . . . . . . 53 7.10 Summary of efficiencies and expected yields . . . . . . . . . . 57 8 Cross Section Measurement 59 8.1 Cross section and uncertainty . . . . . . . . . . . . . . . . . . 59 8.2 The ratio method . . . . . . . . . . . . . . . . . . . . . . . . . 60 8.3 Uncertainty with ratio method . . . . . . . . . . . . . . . . . . 61 8.4 The background box . . . . . . . . . . . . . . . . . . . . . . . 62 9 Systematic Uncertainties 63 9.1 Luminosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 9.2 Theoretical cross section . . . . . . . . . . . . . . . . . . . . . 64 9.3 Jet energy scale . . . . . . . . . . . . . . . . . . . . . . . . . . 65 9.4 B tagging efficiency . . . . . . . . . . . . . . . . . . . . . . . . 65 9.5 Parton Distribution Functions . . . . . . . . . . . . . . . . . . 65 9.6 Amount of pile-up events . . . . . . . . . . . . . . . . . . . . . 67 9.7 Monte Carlo statistics . . . . . . . . . . . . . . . . . . . . . . 67 9.8 Summary of systematic uncertainty . . . . . . . . . . . . . . . 67 10 Significance 69 10.1 Significance estimators . . . . . . . . . . . . . . . . . . . . . . 69 10.2 Estimation of ¢B . . . . . . . . . . . . . . . . . . . . . . . . . 70 8 CONTENTS 10.3 Calculation of the significance . . . . . . . . . . . . . . . . . . 71 11 Conclusion 75 | en |
dc.format.extent | 1446395 bytes | - |
dc.format.mimetype | application/pdf | - |
dc.language | en-US | en |
dc.language.iso | en_US | - |
dc.subject | 夸克 | en |
dc.subject | 單夸克 | en |
dc.subject | 單一夸克 | en |
dc.subject | top | en |
dc.subject | quark | en |
dc.subject | single top | en |
dc.subject | LHC | en |
dc.subject | CMS | en |
dc.title | 尋找與W玻色子共同產生之單一頂夸克 | zh |
dc.title | Search of W-associated Production of Single Top Quarks in CMS | en |
dc.type | thesis | en |
dc.identifier.uri.fulltext | http://ntur.lib.ntu.edu.tw/bitstream/246246/54486/1/ntu-95-R93222005-1.pdf | - |
dc.relation.reference | [1] CDF Collaboration, F. Abe et al., “Observation of top quark production in ‾pp collisions,” Phys. Rev. Lett. 74 (1995) 2626–2631, arXiv:hep-ex/9503002. [2] D0 Collaboration, S. Abachi et al., “Observation of the top quark,” Phys. Rev. Lett. 74 (1995) 2632–2637, arXiv:hep-ex/9503003. [3] Q.-H. Cao and C. P. Yuan, “Single top quark production and decay at next-to-leading order in hadron collisions,” Phys. Rev. D71 (2005) 054022, arXiv:hep-ph/0408180. [4] CDF Collaboration, A. A. Affolder et al., “First measurement of the ratio B(t ! W b)/B(t ! W q) and associated limit on the Cabibbo-Kobayashi-Maskawa element jVtbj,” Phys. Rev. Lett. 86 (2001) 3233–3238, arXiv:hep-ex/0012029. [5] J. Swain and L. Taylor, “First determination of the quark mixing matrix element Vtb from electroweak corrections to Z decays,” Phys. Rev. D58 (1998) 093006, arXiv:hep-ph/9712420. [6] Z. Sullivan, “Understanding single-top-quark production and jets at hadron colliders,” Phys. Rev. D70 (2004) 114012, arXiv:hep-ph/0408049. [7] J. Campbell and F. Tramontano, “Next-to-leading order corrections to Wt production and decay,” Nucl. Phys. B726 (2005) 109–130, arXiv:hep-ph/0506289. [8] S. Zhu, “Next-to-leading order QCD corrections to bg ! tW¡ at the CERN Large Hadron Collider,” Phys. Lett. B 524 (2002) 283–288. 77 78 BIBLIOGRAPHY [9] A. Belyaev and E. Boos, “Single top quark tW + X production at the CERN LHC: A closer look,” Phys. Rev. D63 (2001) 034012, arXiv:hep-ph/0003260. [10] T. M. P. Tait, “tW¡ mode of single top quark production,” Phys. Rev. D61 (2000) 034001, arXiv:hep-ph/9909352. [11] CMS Collaboration, D. Acosta et al., “CMS Physics TDR Volume 1, Section 1.1: The LHC machine,” CERN/LHCC 2006-001 (2006) 2. [12] CMS Collaboration, D. Acosta et al., “CMS Physics TDR Volume 1, Section 1.5: CMS: the overall concept,” CERN/LHCC 2006-001 (2006) 7. [13] CMS Collaboration, A. Cattai et al., “CMS TDR: The Tracker Project,” CERN/LHCC 1998-005 (1998). [14] CMS Collaboration, H. Hofer et al., “CMS TDR: The Electromagnetic Calorimeter Project,” CERN/LHCC 1997-004 (1997). [15] CMS Collaboration, D. Green et al., “CMS TDR: The Hadron Calorimeter Project,” CERN/LHCC 1997-002 (1997). [16] CMS Collaboration, F. Gasparini et al., “CMS TDR: The Muon Project,” CERN/LHCC 1997-003 (1997). [17] CMS Collaboration, S. Cittolin et al., “CMS TDR: The Trigger and Data Acquisition project, Volume2,” CERN/LHCC 2002-006-2 (2002). [18] CMS Collaboration, D. Acosta et al., “CMS Physics TDR Volume 1,” CERN/LHCC 2006-001 (2006). [19] CMS Collaboration, D. Acosta et al., “CMS Physics TDR Volume 1, Section 6.5.1: Vertex fitting,” CERN/LHCC 2006-001 (2006) 261. [20] CMS Collaboration, D. Acosta et al., “CMS Physics TDR Volume 1, Section 10.1: ECAL Clustering and Superclustering,” CERN/LHCC 2006-001 (2006) 365. BIBLIOGRAPHY 79 [21] CMS Collaboration, D. Acosta et al., “CMS Physics TDR Volume 1, Section 2.5.1: Generation of physics events,” CERN/LHCC 2006-001 (2006) 48. [22] S. R. Slabospitsky and L. Sonnenschein, “TopReX generator (version 3.25): Short manual,” Comput. Phys. Commun. 148 (2002) 87–102, arXiv:hep-ph/0201292. [23] T. Sjostrand, L. Lonnblad, S. Mrenna, and P. Skands, “PYTHIA 6.3: Physics and manual,” arXiv:hep-ph/0308153. [24] M. L. Mangano, M. Moretti, F. Piccinini, R. Pittau, and A. D. Polosa, “ALPGEN, a generator for hard multiparton processes in hadronic collisions,” JHEP 07 (2003) 001, arXiv:hep-ph/0206293. [25] CMS Collaboration, D. Acosta et al., “CMS Physics TDR Volume 1, Section 2.5.2: Detailed simulation framework,” CERN/LHCC 2006-001 (2006) 48. [26] CMS Collaboration, D. Acosta et al., “CMS Physics TDR Volume 1, Section 2.7: Event selection and reconstruction,” CERN/LHCC 2006-001 (2006) 65. [27] M. A. Dobbs et al., “Les Houches guidebook to Monte Carlo generators for hadron collider physics,” arXiv:hep-ph/0403045. [28] CMS Collaboration, D. Acosta et al., “CMS Physics TDR Volume 1, Section 12.2: b-tagging tools,” CERN/LHCC 2006-001 (2006) 461. [29] R. A. Fisher, “The use of multiple measurements in taxonomic problems,” Annuals of Eugenics 7 (1936) 179–188. [30] CMS Collaboration, D. Acosta et al., “CMS Physics TDR Volume 1, Section 8.5: Sources of systematic effects,” CERN/LHCC 2006-001 (2006) 229. [31] CMS Collaboration, D. Acosta et al., “CMS Physics TDR Volume 1, Section 11.6.3: °+jet events,” CERN/LHCC 2006-001 (2006) 423. [32] S. Lowette, J. D’Hondt, and J. Heyninck, “Offline Calibration of b-Jet Identification Efficiencies,” CMS Note 2006-013 (2006). 80 BIBLIOGRAPHY [33] P. Bartalini, R. Chierici, and A. De Roeck, “Guidelines for the Estimation of Theoretical Uncertainties at the LHC,” CMS Note 2005-013 (2005). [34] M. Davids, “Uncertainties and Discovery Potential in Planned Experiments,” CMS CR 2002-005 (2002). | en |
item.openairecristype | http://purl.org/coar/resource_type/c_46ec | - |
item.openairetype | thesis | - |
item.languageiso639-1 | en_US | - |
item.grantfulltext | open | - |
item.cerifentitytype | Publications | - |
item.fulltext | with fulltext | - |
顯示於: | 物理學系 |
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