以大型強子對撞機裡的緊湊渺子線圈偵測器尋找重夸克在半輕子頻道衰變成頂夸克和光子

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張祐祥(Yu-hsiang Chang) 查詢紙本館藏

畢業系所

物理學系

論文名稱

以大型強子對撞機裡的緊湊渺子線圈偵測器尋找重夸克在半輕子頻道衰變成頂夸克和光子
(Search for pair production of a heavy quark decaying into top quark and photon in semi-leptonic channel with the CMS detector in the LHC)

相關論文

★ 7 TeV 和2.76 TeV 質子對撞下，光子散射截面積的測量	★ Search for Pair Production of t*-> t + photon : Estimation of Photon Purity and Study of the Top and W Mass Resolution
★ Search for Z′→Zh→llbb in pp Collisions at √s =8 TeV Using the CMS Detector at the LHC	★ Search for heavy resonances decaying into a Z boson and a Higgs boson in the 2l2b final state in pp collisions at √s = 13 TeV
★ 從質子質子對撞在質量中心能量 13 兆電子伏特利用緊湊渺子偵測器尋找重粒子衰變到一對希格斯粒子於四個底夸克最終態	★ Study of the b-tagging Scale Factor using the tt ̅ Events from pp collisions at √s =13 TeV with the CMS Detector
★ 在大型強子對撞機的緊湊渺子線圈偵測器，使用13兆電子伏特的質子-質子對撞尋找會衰變到一對希格斯玻色子且最終狀態為四個底夸克的重共振態	★ 在緊湊渺子線的質心對撞能量為 13 兆電子伏特的數據裡, 用字母法輔以突起搜尋之方法來尋找類 Z 玻色子衰變為 Z 玻色子及希格斯粒子在衰變為輕子與底垮克
★ 在與希格斯玻色子有關聯的暗物質搜索中去測量深度雙底夸克標記校正因子的誤判率	★ The Study of the Di-Higgs Production via Vector Boson Fusion Channel for the Phase II CMS at √? =14 TeV
★ 於尋找單希格斯粒子中研究噴流子結構可觀測量	★ The analysis of the TASEH CD102 data
★ 找尋具有長生命週期新粒子的物理模型所預測的暗物質	★ Toward discovering the low-mass dark matter: Constraints on Searches of Low-mass Weakly Interacting Massive Particle (WIMP) with Earth Attenuation Effect incorporated && Exploring the physics of germanium internal amplification for low-energy detection

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摘要(中)

我們使用CMS在2012年所蒐集的積分亮度為19.7-1 fb、LHC質子對撞質心能量為8 TeV的數據來找尋激發態頂夸克。在我們分析中的衰變過程和最終產物是：激發態頂夸克、反激發態頂夸克->頂夸克、光子、反頂夸克、光子->底夸克、W玻色子、光子、反底夸克、W玻色子、光子，然後其中一個W玻色子以輕子的方式衰變而另一個W玻色子以夸克的方式衰變，所以我們藉著要求事件中有兩個光子、一個輕子和至少四個噴流來定義訊號區域。χ2排序法被用來重建激發態頂夸克的質量，並且從數據中有十二個事件在訊號區域被觀察到。矩陣法被用在兩個光子的頻道裡來估計這十二個事件中的背景貢獻。這個研究的結果是沒有顯著的超過預期的多餘事件被觀察到，所以對於激發態頂夸克的質量我們以95%的信心水準設了一個低限在969 GeV/c2。

摘要(英)

Using the data collected by the CMS detector in 2012, corresponding to a luminosity of 19.7 / fb of proton-proton collisions at LHC center-of-mass energy of 8 TeV, we search for the excited top quark, T*. The decay process and the final states studied in our analysis are: T* T*bar -> t γ tbar γ -> b W+ γ bbar W- γ, where one W boson decays hadronically and the other leptonically, so we define a signal region by requesting events with 2 photons, 1 lepton and >= 4jets. To reconstruct the invariant mass of T*, a χ2-sorting method is used and 12 events are observed in the signal region from data. The matrix method is used to estimate the background contribution among the observed 12 events in the di-photon channel. As a result of this study, no significant excess is observed over expectations and a lower limit is set on a t* quark mass of 969 GeV/c2 at 95% confidence level.

關鍵字(中)

★ 重夸克
★ 緊湊渺子線圈
★ 大型強子對撞機
★ 頂夸克
★ 光子

關鍵字(英)

★ heavy quark
★ CMS
★ LHC
★ top quark
★ photon

論文目次

Contents
Abstract ……………………………………………………………… i
中文提要 ……………………………………………………………… ii
感謝 ……………………………………………………………… iii
Contents ……………………………………………………………… iv
List of table ……………………………………………………………… v
List of figure ……………………………………………………………… vi

Chapter 1 Introduction 1
Chapter 2 LHC and CMS detector 3
2.1 The Large Hadron Collider 3
2.2 The Compact Muon Solenoid Detector 5
2.2.1 Tracker 6
2.2.2 Electromagnetic Calorimeter 9
2.2.3 Hadronic Calorimeter 10
2.2.4 Muon Chamber 12
2.2.5 Magnet system 13
Chapter 3 CMS Trigger 14
3.1 Level-1 trigger 15
3.1.1 Muon triggers system in L1 17
3.1.2 Calorimeter triggers system in L1 17
3.1.2.1 The Electromagnetic Candidate Algorithm 19
3.1.2.2 The Jet Candidate Algorithm 21
3.1.2.3 Other calorimeter trigger tasks 23
3.1.3 Global trigger in L1 24
3.2 High Level trigger 25
3.2.1 electrons/photons 25
3.2.2 Muon 35
3.2.3 Jet 36
3.2.4 Missing transverse energy 37
3.3 The triggers used in our analysis 38
Chapter 4 Event reconstruction in offline and our event selection 39
4.1 The anti-kt jet algorithm 39
4.2 The particle flow (PF) algorithm 41
4.3 The r9 variable and the missing hits 43
4.4 The shower shape variable σiηiη 44
4.5 The isolation variables 45
4.6 The event selection in our analysis 46
Chapter 5 data and the simulated sample 51
Chapter 6 Mass Reconstruction 60
6.1 The χ2-sorting method 60
6.2 The neutrino’s pz solution 62
Chapter 7 background estimation: the matrix method 63
7.1 The introduction of matrix method 63
7.2 the photon fake rate from lepton εl 66
7.3 The photon fake rate from jet εj 68
7.4 The photon signal efficiency εs 72
7.5 The ratio factor 74
Chapter 8 Result 75
Chapter 9 Conclusion 79
Appendix A the derivation of Matrix method 80
Reference 90

List of tables
Table 3.1 the list of the objects sent from GCT to GT 18
Table 3.2 tau decay branching ratio 22
Table 3.3 global trigger menu 24
Table 3.4 parameter of hybrid algorithm 28
Table 3.5 trigger path of our analysis 38
Table 5.1 dataset of our analysis 51
Table 5.2 MC samples used in our analysis 52
Table 5.3 event yields before/after scale factors 53
Table 5.4 event yields in the loose region 59
Table 7.1 fit result of fake rate from jets 71
Table 8.1 event yields in the signal region 77

List of figures
Figure 1.1 The diagram of t* decay 2
Figure 2.1 The CERN accelerator complex 3
Figure 2.2 The main accelerator rings and their beam particles 4
Figure 2.3 The CMS detector 5
Figure 2.4 The CMS coordinate 6
Figure 2.5 The pixel detector 6
Figure 2.6 The pixel material budget 7
Figure 2.7 The layout of tracker 8
Figure 2.8 The layout of tracker 9
Figure 2.9 The layout of ECAL 10
Figure 2.10 The relative positions of ECAL and HCAL 11
Figure 2.11 The relative positions of muon chambers 13
Figure 3.1 The overview of the L1-trigger and the HLT 15
Figure 3.2 the schematic diagram of the data flow in L1-trigger 16
Figure 3.3 the L1-trigger 16
Figure 3.4 The strip, the trigger tower and the calorimeter region grouping 18
Figure 3.5 illustration of the calorimeter trigger e/γ algorithm 20
Figure 3.6 illustration of the calorimeter trigger jet algorithm 22
Figure 3.7 Illustration of the Island clustering algorithm 26
Figure 3.8 Illustration of the super-clusters 27
Figure 3.9 Domino construction step of Hybrid algorithm 27
Figure 3.10 Illustration of the crystal off-pointing and the schematic diagram 30
Figure 3.11 Distribution of Emeas/Etrue 31
Figure 3.12 Emeas/Etrue as a function of the number of crystals 32
Figure 3.13 matching the hits in pixel detector 33
Figure 4.1 anti-kt clustered jets 40
Figure 4.2 consideration of the Bremsstrahlung photon emission of electron 42
Figure 4.3 The schematic diagram of particle flow algorithm 43
Figure 4.4 Missing Hits 44
Figure 4.5 Sketch of the photon isolation 45
Figure 5.1 The number of vertices before/after applying scale factors 54
Figure 5.2 the objects’ multiplicities 55
Figure 5.3 the kinematic distributions 56
Figure 5.4 Four leading jets pT distributions 57
Figure 5.5 Jets’ pT distributions for run dependences 58
Figure 6.1 The invariant mass of a top and a photon using the χ2-sorting method 61
Figure 6.2 The t* mass spectra with different neutrino’s solutions 62
Figure 7.1 the schematic of 3 levels of the events with two photons 64
Figure 7.2 the schematic of the tight, the loose and the FO selection of photon 64
Figure 7.3 Electron-Photon invariant mass fit for the no-electron-veto selection and the tight ID selection 67
Figure 7.4 the object has a photon associated with a jet within the cone of size 0.5 68
Figure 7.5 the schematic of the NjFO and NjT 69
Figure 7.6 Results of the template fitting for the various categories 71
Figure 7.7 Muon-Muon-Photon invariant mass fit for the no-electron-veto selection and the tight ID selection 73
Figure 8.2 The mass spectrum in the signal region 76
Figure 8.3 the exclusion limit 78
Figure A-1 82
Figure A-2 83
Figure A-3 86
Figure A-4 87

參考文獻

Reference
[1]
H. Georgi, L. Kaplan, D. Morin, and A. Schenk, “Effects of top compositeness”,Phys.Rev. D51 (1995) 3888–3894, doi:10.1103/PhysRevD.51.3888,arXiv:hep-ph/9410307.
[2]
E. Eichten, K. D. Lane, and M. E. Peskin, “New Tests for Quark and Lepton
Substructure”, Phys.Rev.Lett. 50 (1983) 811–814, doi:10.1103/PhysRevLett.50.811.
[3]
B. Lillie, J. Shu, and T. M. Tait, “Top Compositeness at the Tevatron and LHC”, JHEP
0804 (2008) 087, doi:10.1088/1126-6708/2008/04/087, arXiv:0712.3057.
[4]
A. Pomarol and J. Serra, “Top Quark Compositeness: Feasibility and Implications”,
Phys.Rev. D78 (2008) 074026, doi:10.1103/PhysRevD.78.074026, arXiv:0806.3247.
[5]
K. Kumar, T. M. Tait, and R. Vega-Morales, “Manifestations of Top Compositeness
at Colliders”, JHEP 0905 (2009) 022, doi:10.1088/1126-6708/2009/05/022,
arXiv:0901.3808.
[6]
B. Moussallam and V. Soni, “PRODUCTION OF HEAVY SPIN 3/2 FERMIONS IN
COLLIDERS”, Phys.Rev. D39 (1989) 1883–1891, doi:10.1103/PhysRevD.39.1883.
[7]
D. A. Dicus, S. Gibbons, and S. Nandi, “Collider production of spin 3/2 quarks”,
arXiv:hep-ph/9806312.
[8]
W. Rarita and J. Schwinger, “On a theory of particles with half integral spin”,
Phys.Rev. 60 (1941) 61, doi:10.1103/PhysRev.60.61.
[9]
B. Hassanain, J. March-Russell, and J. Rosa, “On the possibility of light string
resonances at the LHC and Tevatron from Randall-Sundrum throats”, JHEP 0907
(2009) 077, doi:10.1088/1126-6708/2009/07/077, arXiv:0904.4108.
[10]
L. Randall and R. Sundrum, “A Large mass hierarchy from a small extra dimension”,
Phys.Rev.Lett. 83 (1999) 3370–3373, doi:10.1103/PhysRevLett.83.3370,
arXiv:hep-ph/9905221.
[11]
W. Stirling and E. Vryonidou, “Effect of spin-3/2 top quark excitation on tt¯
production at the LHC”, JHEP 1201 (2012) 055, doi:10.1007/JHEP01(2012)055,
arXiv:1110.1565.
[12]
Fang-Ying Tsai, “Search for Pair Production of t*-> t + photon : Estimation of
Photon Purity and Study of the Top and W Mass Resolution”,
http://etd.lib.nctu.edu.tw/cgi-bin/gs32/ncugsweb.cgi/ccd=drnGQv/record?r1=2&h1=
0
[13]
The CMS Collaboration, The CMS tracker system project: Technical Design Report.
Technical Design Report CMS, Geneva: CERN, 1997. 2.2.3
[14]
The CMS Collaboration, TheCMS tracker: addendum to the Technical Design Report.
Technical Design Report CMS, Geneva: CERN, 2000. 2.2.3
[15]
The CMS ECAL: Technical Design Report. Technical Design Report, Geneva: CERN,
December1997. 2.2.4
[16]
P.Bloch, R. Brown, P.Lecoq, and H. Rykaczewski, Changes to CMS ECAL electronics:
addendum to the Technical Design Report. Techical Design Report CMS, Geneva: 58
CERN, 2002. 2.2.4
[17]
CMS Collaboration, CERN/LHCC 20-016(2006), CMS TDR 8.1
[18]
The CMS Collaboration, The CMS hadron calorimeter project: Technical Design
Report. Technical Design Report CMS, Geneva: CERN, 1997. 2.2.5
[19]
J. Damgov and S. Kunori, private commuication
[20]
Efe Yazgan, Thesis, Department of Physics, Middle East Technical University (2007)
[21]
Andrew W. Rose. The Level-1 Trigger of the CMS experiment at the LHC and the
Super-LHC. University of London and the Diploma of Imperial College (2009).
https://workspace.imperial.ac.uk/highenergyphysics/Public/theses/Rose.pdf
[22]
J. Brooke, Performance of the CMS Level-1 Trigger, arXiv:1302.2469(2013).
http://arxiv.org/abs/1302.2469
[23]
The TriDAS Project, Technical Design Report, Volume 1: The Trigger Systems. CMS
(2000). http://cmsdoc.cern.ch/cms/TDR/TRIGGER-public/trigger.html
[24]
Giuseppe Bagliesi. Reconstruction and identification of tau decays at CMS. J. Phys.:
Conf. Ser. 119 032005 doi:10.1088/1742-6596/119/3/032005 (2008)
http://iopscience.iop.org/1742-6596/119/3/032005
[25]
The CMS High Level Trigger, http://arxiv.org/ftp/hep-ex/papers/0512/0512077.pdf
[26]
Electron Reconstruction in the CMS Electromagnetic Calorimeter
http://cds.cern.ch/record/687345/files/note01_034.pdf
[27]
S. Baffioni et al. Electron reconstruction in CMS. Eur. Phys. J. C 49, 1099–1116
(2007) DOI 10.1140/epjc/s10052-006-0175-5
http://inspirehep.net/record/713909/files/NOTE2006_040.pdf?version=1
[28]
R. Fr¨uhwirth, Application of Kalman filtering to track and vertex fitting, Nucl.
Instrum. Meth. A 262(1987) 444.
[29]
CMS collaboration, The CMS Physics Technical Design Report, Volume I: Detector
Performance and Software, CERN-LHCC-2006-001, CMS-TDR-8.1 (2006).
[30]
Ricardo Eusebi, Jet energy corrections and uncertainties in CMS: reducing their
impact on physics measurements, Journal of Physics: Conference Series 404 (2012)
012014 doi:10.1088/1742-6596/404/1/012014
[31]
Outer link of trigger path
http://j2eeps.cern.ch/cms-project-confdb-hltdev/browser/
For example, the run range 196531, one can go to the link, in left window choose:
online->collisions->2012->7e33->v2.5->HLT, and in the right window choose:
A->SingleElectron, and find the HLT
path”HLT_Ele25_CaloIdVT_CaloIsoT_TrkIdT_TrkIsoT_TriCentralPFNoPUJet30_30_20”.
The L1 triggers “L1_SingleEG20 or L1_SingleEG22” can also be found in the right
most of trigger path.
[32]
Matteo Cacciari, Gavin P. Salam, Gregory Soyez, The anti-kt jet clustering algorithm,
JHEP 0804:063,2008,arXiv:0802.1189 [hep-ph]
[33]
S. Catani, Y. L. Dokshitzer, M. H. Seymour and B. R. Webber, Nucl. Phys. B 406 (1993)
187 and refs. therein; S. D. Ellis and D. E. Soper, Phys. Rev. D 48 (1993) 3160
[hep-ph/9305266].
[34]
Y. L. Dokshitzer, G. D. Leder, S. Moretti and B. R. Webber, JHEP 9708, 001 (1997)
[hep-ph/9707323]; M. Wobisch and T. Wengler, hep-ph/9907280.
[35]
Florian Beaudette, The CMS Particle Flow Algorithm, Proceedings of the
CHEF2013 Conference - Eds. J.C. Brient, R. Salerno, and Y. Sirois - p295 (2013), ISBN
978-2-7302-1624-1arXiv:1401.8155 [hep-ex]
[36]
CMS Collaboration. Particle-Flow Event Reconstruction in CMS and Performance for
Jets, Taus and EmissT . (CMS-PAS-PFT-09-001), 2009.
[37]
https://agenda.linearcollider.org/getFile.py/access?contribId=3&sessionId=1&re
sId=1&materialId=slides&confId=5037
[38]
Adam, Wolfgang and Frühwirth, R. and Strandlie, Are and Todor, T. Reconstruction
of Electrons with the Gaussian-Sum Filter in the CMS Tracker at the LHC. 2005.
[39]
P. Fayet, Nucl.Phys. B 90, 104 (1975).
[40]
Tracking and Primary Vertex Results in First 7 TeV
Collisions, CMS PAS TRK-10-005(2010),
https://cds.cern.ch/record/1279383/files/TRK-10-005-pas.pdf
[41]
https://twiki.cern.ch/twiki/bin/view/CMSPublic/SWGuideMuonId.
electron
[42]
https://twiki.cern.ch/twiki/bin/viewauth/CMS/TWikiTopRefEventSel#Electrons.
[43]
https://twiki.cern.ch/twiki/bin/view/CMS/MultivariateElectronIdentification.
[44]
https://twiki.cern.ch/twiki/bin/view/CMS/CutBasedPhotonID2012
[45]
M. Cacciari, G. P. Salam, and G. Soyez, “The Anti-k(t) jet clustering algorithm”, JHEP
0804 (2008) 063, doi:10.1088/1126-6708/2008/04/063, arXiv:0802.1189
[46]
F. Maltoni and T. Stelzer, “MadEvent: Automatic event generation with MadGraph”,
JHEP 0302 (2003) 027, arXiv:hep-ph/0208156.
[47]
J. Pumplin et al., “New generation of parton distributions with uncertainties from
global QCD analysis”, JHEP 0207 (2002) 012, arXiv:hep-ph/0201195.
[48]
T. Sjo¨ strand, S. Mrenna, and P. Z. Skands, “PYTHIA 6.4 Physics and Manual”, JHEP
0605 (2006) 026, doi:10.1088/1126-6708/2006/05/026, arXiv:hep-ph/0603175.
[49]
S. Alioli, P. Nason, C. Oleari, and E. Re, “NLO single-top production matched with
shower in POWHEG: s-and t-channel contributions,”JHEP 0909(2009) 111, arXiv:
0907.4076 [hep-ph].
[50]
E. Re, “Single-top Wt-channel production matched with parton showers using the
POWHEG method,”Eur.Phys.J. C71(2011) 1547, arXiv: 1009. 2450 [hep-ph].
[51]
S. Agostinelli et al., “Geant4-A Simulation Toolkit,”Nuclear Instruments and
Methods A 506(2003).
[52]
G. Cowan, K. Cranmer, E. Gross, and O. Vitells, “Asymptotic formulae for
likelihood-based tests of new physics”, The European Physical Journal C 71 (2011),
no. 2, 1–19, doi:10.1140/epjc/s10052-011-1554-0, arXiv:1007.1727.

指導教授

余欣珊(Shin-Shan Yu)

審核日期

2014-7-21

推文