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http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/1251完整後設資料紀錄
| DC 欄位 | 值 | 語言 |
|---|---|---|
| dc.contributor.advisor | 張寶棣 | |
| dc.contributor.author | Chang-Ming Cheng | en |
| dc.contributor.author | 程章銘 | zh_TW |
| dc.date.accessioned | 2021-05-12T09:34:56Z | - |
| dc.date.available | 2018-05-17 | |
| dc.date.available | 2021-05-12T09:34:56Z | - |
| dc.date.copyright | 2018-05-17 | |
| dc.date.issued | 2018 | |
| dc.date.submitted | 2018-04-16 | |
| dc.identifier.citation | [1] HiggsTan. http://higgstan.com/standerd-model/.
[2] Wikimedia Commons. https://commons.wikimedia.org/wiki/File:Elementary_particle_interactions_in_the_Standard_Model.png. [3] K.A. Olive et al. (Particle Data Group). Review of Particle Physics. Chin. Phys. C, 38(090001), 2014. [4] K. Abe et al. (Belle Collaboration). Observation of Large CP Violation in the Neutral B Meson System. Phys. Rev. Lett., 87(091802), 2001. [5] HyperPhysics. http://hyperphysics.phy-astr.gsu.edu/hbase/Particles/expar.html. [6] Discovery of the Bottom Quark. http://www.fnal.gov/pub/inquiring/physics/discoveries/bottom_quark_pr.html. [7] D. Besson and T. Skwarnicki. UPSILON SPECTROSCOPY: Transitions in the BotBottomonium System. Annu. Rev. Nucl. Part. Sci., 43:333–78, 1993. [8] J. Beringer et al. (Particle Data Group). Review of Particle Physics. Phys. Rev. D, 86(010001), 2012. [9] Brian Batell, Maxim Pospelov, and Adam Ritz. Multi-lepton Signatures of a Hidden Sector in Rare B Decays. Phys. Rev. D, 83(054005), 2011. [10] S. V. Demidov and D. S. Gorbunov. Flavor violating processes with sgoldstino pair production. Phys. Rev. D, 85(077701), 2012. [11] Dmitri Melikhov and Nikolai Nikitin. Rare radiative leptonic decays Bd,s→l+l-γ. Phys. Rev. D, 70(114028), 2004. [12] R. Aaij et al. (LHCb Collaboration). Search for rare B0(s)→μ+μ-μ+μ- decays, Phys. Rev. Lett., 110(211801), 2013. [13] KEKB. http://www2.kek.jp/accl/introKEKB/. [14] Wikimedia Commons. https://commons.wikimedia.org/wiki/File:KEKB.png. [15] A. Abashian et al. (Belle Collaboration). The Belle detector. Nuclear Instruments and Methods in Physics Research A, 479:117–232, 2002. [16] L. Hinz. Lepton ID efficiency correction and systematic error. Belle Note 954, 2006. [17] Z. Natkaniec et al. (Belle SVD2 Group). Belle SVD2 Vertex Detector. Nucl. Instrum. Methods Phys. Res. Sect. A, 568, 1:269–273, 2006. [18] K. Hanagaki et al. Electron Identification in Belle. Nucl. Instrum. Methods Phys. Res. Sect. A, 485:490–503, 2002. [19] BASF Overview (Belle internal). http://belle.kek.jp/secured/wiki/doku.php?id=software:basf. [20] The EvtGen package home page. http://www.slac.stanford.edu/~lange/EvtGen/. [21] CLEO. https://www.classe.cornell.edu/Research/CLEO/. [22] BaBar. http://www.slac.stanford.edu/BFROOT/. [23] Anders Ryd et al. EvtGen A Monte Carlo Generator for B-Physics. http://evtgen.hepforge.org/doc/EvtGenGuide.pdf. [24] CERN. https://home.cern/. [25] CERN. GEANT Detector Description and Simulation Tool. [26] ROOT Users Guide. https://root.cern.ch/root/htmldoc/guides/users-guide/ROOTUsersGuide.html. [27] Wikimedia. https://en.wikipedia.org/wiki/Monte_Carlo_method. [28] Wikimedia. https://en.wikipedia.org/wiki/Observer-expectancy_effect. [29] Ohio State University Department of Physics. https://www.physics.ohio-state.edu/~gan/teaching/spring04/Chapter6.pdf. [30] UW Madison Department of Astronomy. http://www.astro.wisc.edu/~bank/. [31] Giovanni Punzi. Sensitivity of Searches for New Signals and Its Optimization. PHYSTAT2003, SLAC, Stanford, 2003. [32] C. Patrignani et al. (Particle Data Group). Review of Particle Physics. Chin. Phys. C, 40(100001), 2016. [33] Ryosuke Itoh. Measurements of Polarization CP Asymmetry in B→J/ψK* decays. Belle note 487, 2001. [34] Gary J. Feldman and Robert D. Cousins. A Unified Approach to the Classical Statistical Analysis of Small Signals. Phys. Rev. D, 57(3873), 1998. | |
| dc.identifier.uri | http://tdr.lib.ntu.edu.tw/handle/123456789/1251 | - |
| dc.description.abstract | 本論文利用蒙地卡羅方法模擬日本高能加速器B介子工廠(KEKB)中之Belle偵測器所收集的771百萬個B介子對與背景來尋找B0介子衰變至四個輕子的事件，其中包含三種衰變模式B0→μ+μ-μ+μ-、B0→e+e-e+e-和B0→e+e-μ+μ-。我們使用NeuroBayes演算法來分離訊號與背景以提升訊噪比，接著再以B0介子衰變至一個J/ψ介子、一個K介子和一個π介子，J/ψ介子再衰變至一個輕子對的事件作為對照組來確認分析步驟是否正確並得到校正因子，然後利用校正因子作為B0→l+l-l+l-之中模擬與數據的校正。最後我們估計在90%的信賴區間之下的衰變機率上限為： B(B0→μ+μ-μ+μ-)<1.28×10E-7，B(B0→e+e-e+e-)<8.34×10E-8和B(B0→e+e-μ+μ-)<5.09×10E-8。 | zh_TW |
| dc.description.abstract | This thesis uses Monte Carlo method to simulate 771 million BB pairs and background collected in Belle detector at KEKB to search for B0→l+l-l+l-, it includes B0→μ+μ-μ+μ-, B0→e+e-e+e- and B0→e+e-μ+μ-. We use NeuroBayes algorithm to separate signal from background so that it enhances the signal-to-noise ratio, then we do B0→J/ψ(J/ψ→l+l-)K+π- as the control sample to check whether the analysis is correct or not and get the calibration factor, and then we use calibration factor to be the correction between simulation and data in B0→l+l-l+l-. Finally, we estimate the upper limit of branching fraction at 90% confidence interval: B(B0→μ+μ-μ+μ-)<1.28×10E-7, B(B0→e+e-e+e-)<8.34×10E-8 and B(B0→e+e-μ+μ-)<5.09×10E-8. | en |
| dc.description.provenance | Made available in DSpace on 2021-05-12T09:34:56Z (GMT). No. of bitstreams: 1 ntu-107-R03222050-1.pdf: 7035440 bytes, checksum: 2ad2e94deb5700ad0e471111682a9593 (MD5) Previous issue date: 2018 | en |
| dc.description.tableofcontents | 口試委員會審定書 iii
誌謝 v 摘要 vii Abstract ix 1 Introduction 1 1.1 Particle Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Standard Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2.1 Cabibbo-Kobayashi-Maskawa Matrix . . . . . . . . . . . . . . . 3 1.2.2 CP Violation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2.3 Feynman Diagram . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.3 B Meson Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.4 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2 Belle Experiment 11 2.1 KEKB Accelerator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.2 Belle Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.2.1 Beam Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.2.2 Silicon Vertex Detector (SVD) . . . . . . . . . . . . . . . . . . . 19 2.2.3 Extreme Forward Calorimeter (EFC) . . . . . . . . . . . . . . . 19 2.2.4 Central Drift Chamber (CDC) . . . . . . . . . . . . . . . . . . . 21 2.2.5 Aerogel Cherenkov Counters (ACC) . . . . . . . . . . . . . . . . 22 2.2.6 Time-of-Flight Counters (TOF) . . . . . . . . . . . . . . . . . . 25 2.2.7 Electromagnetic Calorimeter (ECL) . . . . . . . . . . . . . . . . 26 2.2.8 KL and Muon Detector (KLM) . . . . . . . . . . . . . . . . . . 28 3 B Event Reconstruction 31 3.1 Analysis Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 3.1.1 BASF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 3.1.2 EvtGen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 3.1.3 GSIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3.1.4 ROOT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3.2 Blind Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3.3 Data Sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 3.4 Particle Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 3.4.1 Electron Identification . . . . . . . . . . . . . . . . . . . . . . . 35 3.4.2 Muon Identification . . . . . . . . . . . . . . . . . . . . . . . . 35 3.5 Event Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 3.5.1 Charged Track Requirements . . . . . . . . . . . . . . . . . . . . 35 3.5.2 Multiple Candidates Selection . . . . . . . . . . . . . . . . . . . 36 3.5.3 Bremsstrahlung Recovery . . . . . . . . . . . . . . . . . . . . . 36 3.5.4 Signal Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.6 Background Suppression . . . . . . . . . . . . . . . . . . . . . . . . . . 39 3.6.1 Continuum Background . . . . . . . . . . . . . . . . . . . . . . 40 3.6.2 NeuroBayes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 3.6.3 Generic B Background . . . . . . . . . . . . . . . . . . . . . . . 44 3.6.4 Figure of Merit . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 3.7 Signal Extraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 3.7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 3.7.2 Modelling for Probability Density Function . . . . . . . . . . . . 47 4 Control Sample Study 53 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 4.2 Particle Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 4.3 Event Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 4.4 Background Suppression . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4.4.1 Continuum Background . . . . . . . . . . . . . . . . . . . . . . 55 4.4.2 Generic B Background . . . . . . . . . . . . . . . . . . . . . . . 56 4.5 Signal Extraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 4.6 Calibration Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 4.6.1 Calibration Factor Result . . . . . . . . . . . . . . . . . . . . . . 61 4.6.2 Branching Fraction . . . . . . . . . . . . . . . . . . . . . . . . . 62 5 Conclusion 63 5.1 Data Fitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 5.2 Upper Limit Estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 5.3 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Bibliography 67 | |
| dc.language.iso | en | |
| dc.title | 尋找B0介子衰變至l+l-l+l-之分析 | zh_TW |
| dc.title | Search for B0→l+l-l+l- Decay at Belle | en |
| dc.type | Thesis | |
| dc.date.schoolyear | 106-2 | |
| dc.description.degree | 碩士 | |
| dc.contributor.oralexamcommittee | 王名儒,徐靜戈 | |
| dc.subject.keyword | 貝爾實驗,B介子,輕子, | zh_TW |
| dc.subject.keyword | Belle experiment,B meson,Lepton, | en |
| dc.relation.page | 69 | |
| dc.identifier.doi | 10.6342/NTU201800725 | |
| dc.rights.note | 同意授權(全球公開) | |
| dc.date.accepted | 2018-04-17 | |
| dc.contributor.author-college | 理學院 | zh_TW |
| dc.contributor.author-dept | 物理學研究所 | zh_TW |
| 顯示於系所單位： | 物理學系 | |
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