声明
摘要
Abstract
Contents
Preface
1 Introduction
1．1The Standard Model
1．2The Quark Model
1．3Quantum chromodynamics
1．4Scattering and factorisation
1．4．1Deep inelastic scattering
1．5Parton distribution functions
1．6Electroweak unification
1．7 Doubly charmed bayron
1．7．1 Theoretical predictions
1．7．2Various experiments searched DCBs in the past decades
1．8Angular Coefficient
1．8．1Introduction
1．8．2Dilution effects
1．8．3The Lam-Tung relation
1．8．4The Boer-Mulders funetion
1．8．5The weak mixing angle
1．8．6Previous studies
1．8．7Strategy
2The LHCb Detector
2．1LHC
2．2 The LHCb Detector
2．3Tracking system
2．3．1Vbrtex Locator
2．3．2Tracking Detectors
2．3．3Spectrometer Magnet
2．3．4Track finding algorithm
2．3．5Track finding efficiency and momentum resolution
2．4Particle Identification
2．4．1Ring Imaging Cherenkov Detectors
2．4．2Calorimeter System
2．5Muon System
2．6Triggering at LHCb
2．6．1Level-0 trigger
2．6．2 High level trigger
2．7LHCb software framework
2．8LHCb Upgrade
3Ghost probability study for LHCb RunⅢ
3．1Introduction
3．2Track reconstruction
3．3Reconstruction sequence in Runll and the upgrade
3．4Fake track
3．5The ghost probability classifier for long tracks
3．5．1Introduction
3．5．2Previous works
3．6Ghost probability study for LHCb RunⅢ
3．6．1Input variables
3．6．2Active function-hidden layer
3．6．3 Active function-last layer
3．6．4Output transformation
3．7Conclusion
4LHCb Scintillating Fibre Tracker：the CERN-SPS July 2018 test beam studies
4．1Introduction
4．1．1LHCb Upgrade
4．1．2Requirements
4．1．3Tbst Bcam
4．2LHCb SciFi detectors design
4．2．1Layout of the LHCb SeiFi
4．2．2 Working principle
4．2．3Scintillating fibres
4．2．4Fibre mats and modules
4．2．5Silicon photomultipliers
4．2．6Fronted electronics
4．2．7Light injection system
4．2．8Hit reconstruction
4．3The PACIFIC ASIC
4．3．1Input stage
4．3．2Fast shaper
4．3．3Integration
4．3．4Digitisation
4．4Test Beam in July 2018
4．4．1Experimental setup
4．4．2Calibration of the PACIFIC threshold
4．4．3Event selection
4．4．4Fine Timestamp Selection
4．4．5Single Hit Efficiency
4．4．6Studies of the single hit resolution
5 Search for the doubly charmed baryon Ξcc++ with the Ξc+π+ decay
5．1Data and simulation
5．2Selection
5．2．1Overview
5．2．2 Selections in the trigger
5．2．3Offline reconstruction and preselection
5．2．4Multivariate selection
5．2．5Removal of internal track clone candidates
5．2．6Duplicate candidates
5．3Studies of the backgrounds
5．3．2Multiple candidates
5．3．3 Clone traeks
5．4 Measurement of Ξcc++ mass
5．4．1 Mass fitting
5．4．2 Momentum scaling calibration
5．4．3 Bias of the Ξc+ mass
5．4．4 Bias of Ξcc++ mass due to offline selections
5．4．5 Uncertainty on Ξc+ mass
5．4．6 Invariant mass fit model
5．4．7 Stability with respect to MVA selection
5．4．8 Unblinded resuits
5．4．9 Summary of mass measurement
5．5 Ratio of branching fraction measurement
5．5．1 Signal modeling
5．5．2 Emeiencies
5．5．3 Trigger efficiency
5．6 Total efficiency and ratio
5．6．1 Ratio of branching fraction results
5．7 Procedures for evaluating significance and setting limits
5．7．1 Strategy
5．7．2 Local significance estimates
5．7．3 Global significance estimates
5．7．4 Upper limits
5．8 Conclusions
6Measurement of the angular coefficients of μ+μ- pairs in the Z boson mass region at LHCb
6．1Data and simulation samples
6．1．1Data samples
6．1．2Simulation
6．1．3MC with detector simulation
6．1．4Generator level MC
6．2Event selection
6．2．1Trigger
6．2．2Stripping
6．2．3Oflline selection
6．3Backgrounds
6．3．1Semileptonic heavy flavour decays
6．3．2Hadron mis-identification
6．3．3Top and EW productions
6．4Corrections
6．4．1Muon momentum calibration
6．4．2Muon momentum smearing for MC events
6．4．3Background subtraction
6．4．4Efficiency
6．4．5 Data／MC reweight
6．4．6Data and MC comparisons
6．5Fitting method
6．5．1Method introduetion
6．5．2Efficiency correction
6．5．3Normalization weights
6．5．4Validation
6．6Systematic uncertainties
6．6．1Efficiency
6．6．2MC sample size
6．6．3Baekground estimation
6．6．4PDFs uncertainties
6．6．5Acceptance reweighting
6．6．6Summary of systematic uncertainty
6．7Measured Ai results
6．7．1 Z boson pT depended results
6．7．2Z boson rapidity depended results
6．7．3Results with low Z boson pT events
6．8Conclusion
7 Measurements of high-pT muon reconstruction efficiency for the LHCb RunⅡ data-sets
7．1Introduction
7．2Trigger efficiency
7．2．1Tag-and-Probe selection
7．2．2Baekground estimation
7．3MC muon trigger efficiency
7．3．1Systematic uncertainties
7．3．2Results
7．4Tracking efficiency
7．4．1Probe track
7．4．2Tag-and-Probe selection
7．4．3Baekground estimation
7．4．4Corrections
7．4．6Track Matching Efficiency
7．4．7 Monte-Carlo Comparison
7．5The corrected tracking efficiency
7．5．1Track matching efficiency systematic uncertainty
7．5．2MuonTT finding systematic uncertainty
7．5．3Total systematic uncertainty
7．6Results
7．7Identification efficiency
7．7．1Tag-and-Probe selection
7．7．2MC muon identification efficiency
7．7．3Background estimation
7．7．4Systematic uncertainties
7．7．5Results
7．8Conclusion
8Improved—alignment andmomentum calibration forphysics with high momentum muons in LHCb
8．1Introduction
8．2Samples and event selection
8．3Detector alignment update
8．3．1TT／IT／OT alignment
8．3．2 VELO alignment
8．3．3Summary of‘Improved-alignment’
8．4Post-alignment
8．4．1The Z0 mass dependence in generator level
8．4．2Procedures of‘Post-alignment’
8．4．3 Muon η tuning
8．4．4Muon φ tuning
8．4．5‘Post-alignment’results
8．5MC muon momentum corrections
8．6MC muon momentum resolution check
8．7Systematic uncertainty
8．8Conclusions
攻读博士学位期间完成的工作
Appendices
References
致谢
华中师范大学;
