Experimental investigation of double-pion production in proton-proton interactions [Elektronische Ressource] / von Tamer Tolba

Tolba, Youssef Tamer

Sujets

• Physik

Informations

• Publié par: ruhr-universitat_bochum
• Publié le: 01 janvier 2010
• Nombre de lectures: 41
• Langue: English
• Poids de l'ouvrage: 9 Mo

Extrait

Experimental Investigation of Double-
Pion Production in Proton-Proton
Interactions


DISSERTATION

zur
Erlangung des Grades
„Doktor der Naturwissenschaften“

an der Fakultät für Physik und Astronomie
der Ruhr-Universität Bochum


von
Tamer Tolba

aus
Kairo-Ägypten


Bochum 2010




















1
1. Gutachter: Prof. Dr. James Ritman
22. Gutachter: Prof. Dr. Ulrich Wiedner

Datum der Disputation: 05.11.2010


1
Forschungszentrum Jülich, Ruhr-Universität Bochum
2
Ruhr-Universität Bochum. Table of contents I
Table of contents

Zusammenfassung .................................................................................................1
Introduction............................................................................................................2
1. Theoretical Motivation......................................................................................5
2. Experimental Setup .........................................................................................11
2.1 The COSY Storage Ring .................................................................................12
2.2 The WASA Facility .........................................................................................14
2.2.1 The Pellet Target.......................................................................................15
2.2.2 The Central Detector (CD) .......................................................................18
2.2.2.1 The Mini Drift Chamber (MDC) .......................................................18
2.2.2.2 The Plastic Scintillator Barrel (PSB).................................................19
2.2.2.3 The SuperConducting Solenoid (SCS) ..............................................22
2.2.2.4 The Scintillating Electromagnetic Calorimeter (SEC) ......................23
2.2.3 Forward Detector (FD) .............................................................................25
2.2.3.1 The Forward Window Counter (FWC)..............................................26
2.2.3.2 The Forward Proportional Chamber (FPC) .......................................26
2.2.3.3 The Forward Trigger Hodoscope (FTH) ...........................................28
2.2.3.4 The Forward Range Hodoscope (FRH).............................................28
2.2.3.5 The Forward Range Intermediate Hodoscope (FRI) .........................30
2.2.3.6 The Forward Veto Hodoscope (FVH) ...............................................30
2.2.3.7 The Forward Range Absorber (FRA) ................................................30
2.3. Data Acquisition System (DAQ)....................................................................32
2.4 Trigger System.................................................................................................33
2.5 Analysis Tools .................................................................................................34
2.5.1 RootSorter.....................................................................................................35 Table of contents II
2.5.2 Event Generator............................................................................................35
2.5.2.1 Pluto++ ..................................................................................................35
2.5.2.2 Geant INput (GIN).................................................................................36
2.5.3 WASA Monte Carlo (WMC)........................................................................37
3. Detector Calibration and Track Reconstruction..........................................38
3.1 Calibration .......................................................................................................38
3.1.1 Scintillating Electromagnetic Calorimeter ...............................................38
3.1.2 Forward Detector......................................................................................40
3.2 Track Reconstruction.......................................................................................43
3.2.1 Photon Reconstruction..............................................................................43
3.2.2 Forward Detector Track Reconstruction ..................................................45
3.3 Particle Identification.......................................................................................46
3.4 Reconstruction of the Kinetic Energy..............................................................47
4. Data Selection...................................................................................................51
4.1. Data Collection ...............................................................................................52
4.2. Track Selection ...............................................................................................52
4.2.1 Selection of Charged Tracks in the FD.....................................................53
4.2.2 Selection of Neutral Tracks in the CD......................................................55
4.3 Event Selection ................................................................................................55
4.4 Proton Identification in the FD ........................................................................57
4.5 Pion Reconstruction in the CD ........................................................................58
4.6 Constraints on the Geometrical Boundaries of the Detector ...........................58
4.7 Kinematical Fit (KFit) .....................................................................................60
4.7.1 Error Estimate...........................................................................................61
4.7.2 Photon Pair Selection................................................................................65
4.7.3 Probability Distribution ............................................................................65
4.8 Comparison of Data and MC Results ..............................................................67
5. Acceptance Corrections and Absolute Normalization .................................71 Table of contents III
5.1 Acceptance Correction.....................................................................................71
5.1.1 Model Independent Acceptance Correction .............................................72
5.1.2 Model Dependent Acceptance Correction................................................78
5.2 Luminosity Studies ..........................................................................................81
0
5.2.1 pp→ppη(→3π →6γ) as the Reference Reaction......................................83
5.2.2 pp→ppη(→2γ) as the Reference Reaction ...............................................85
6. Results and Discussion ....................................................................................89
6.1 Evaluation of the Measurement Uncertainties.................................................90
6.1.1 Statistical Error .........................................................................................90
6.1.2 Systematical Error ....................................................................................90
6.1.2.1 Luminosity Corrections .....................................................................90
6.1.2.2 Acceptance Correction.......................................................................91
6.1.2.3 Confidence Level of the KFit ............................................................91
6.1.4 Detector Boundaries .................................................................................93
0 06.2 pp→ppπ π Total Cross Section ......................................................................94
6.3 Differential Cross Section Distributions..........................................................96
7. Pellet Tracking System..................................................................................102
7.1 Main Concept.................................................................................................102
7.2 Experimental Equipment ...............................................................................103
7.2.1 Line Scan Camera...................................................................................103
7.2.2 Laser .......................................................................................................105
7.2.3 Frame Grabber ........................................................................................105
7.3 Optimization of the Setup..............................................................................105
7.3.1 Lens-Target Distance Optimization........................................................105
7.3.2 Pixel Size Calibration .............................................................................107
7.3.3 Hair Thickness Measurement .................................................................108
7.3.4 Time Calibration.....................................................................................110
7.4 Previous Work on the PTS at the The Svedberg Laboratory.........................111 Table of contents IV
7.5 Moscow-Jülich Pellet Target ...