R-1237 CU-403 Nevis-297

R-1237 CU-403 Nevis-297 ColuInbia University Department of Physics New York, New York 10027 MEASUREMENTS OF R10ng AND IVcs I FROM THE CCFR EXPERIMENT Cynthia Kay McNulty Reproduction in whole or in part is permitted for any purpose by the United States Government. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Gradauate School of Arts and Sciences COLUMBIA UNIVERSITY National Science Foundation NSF PHY 95-12810 1997 - - - - - ... - ... - - - - - .... - MEASUREMENTS OF Rlong AND IVes I FROM THE CCFR EXPERIMENT Cynthia Kay McNulty Columbia University, New York, NY * Research supported by the National Science Foundation. t Submitted in partial fulfillment of the requirement for the degree of Doctor of Philosophy in the Graduate School of Arts and Sciences, ColuITlbia University. - Abstract v v The four structure functions F2 , R long' xF3 ' and xF3 are extracted from measurements of inclusive charged-current v-Fe interactions in the CCFR detector at the Fermilab Tevatron. The analysis produces measurements of ~:~~ the CKM matrix element IVes I = 1.05 ± 0.1 0 and measurements of 2 2 ~ ~ ~ ~ R long made at 0.0 x 0.425 and 1 Q 100 GeV . The new R long measurements probe a low-x kinematic region (x = 0.01) which is important for constraining the gluon distribution. - - - - - - - - Table of Contents Table of Contents i List of Figures ' iv List of Tables vi 1 Introduction 1 1.1 The Standard Model 3 1.2 Neutrino-Nucleon Scattering 8 1.3 Kinematics of a Charged-Current n Event. 10 1.4 The Formalism of Deep-Inelastic Scattering 13 - 1.5 The Parton Model 17 1.6 The Strange Sea 24 - 1.7 QCD 25 1.8 The Structure Function RZong •.••..••.....•...••.•.•••.•.•...•.......••.••.......••..•.....•...27 1.9 Analysis Overview 31 2 The Neutrino Beam and Detector 34 2.1 Neutrinos at the Fermilab Tevatron 35 2.2 Neutrino Beam 40 2.3 Detector 42 2.3.1 Target Calorimeter 43 2.3.1.1 Scintillator Counters 44 2.3.1.2 Drift Chambers 48 2.3.2 Muon Spectrometer 51 2.4 Data Acquisition 54 2.4.1 The Trigger System 55 -. 2.4.1.1 The Phototube Signals 56 2.4.1.2 The Six Main Event Triggers 63 2.4.2 Data Collection 64 3 Calibration and Data Analysis 66 3.1 Hadron Energy Measurement 66 c- 3.1.1 Counter Gain Calibration 67 3.1.2 Map and Time Variation Corrections 70 3.1.3 Calorimeter Energy Calibration 73 3.1.4 Hadron Energy Calculation 80 3.2 Muon Angle and Momentum Measurement 81 3.2.1 Muon Tracking Procedure 81 3.2.2 Muon Angle Measurement. 83 3.2.3 Muon Momentum Measurement. 84 -.. 3.2.4 Muon Energy Calculation 88 3.3 Analysis Cuts 90 ... 3.3.1 Fiducial-Volume Cuts 90 3.3.2 Geometric Cuts 91 3.3.3 Cross-section Cuts 92 - 3.3.4 Structure-Function Cuts 92 4 The Monte Carlo 95 ... 4.1 NUMONTE versus the Fast MC 95 4.2 Event Generation 96 4.3 Resolution Smearing 99 - 4.4 Muon Energy Loss 100 4.5 The Physical Cross-section 101 4.5.1 Isoscalar Correction 102 4.5.2 Radiative Correction 104 4.5.3 Charm Production Threshold 105 4.5.4 Propagator Correction 109 4.3 Dimuon Events 110 5 Iteratively Determined Flux and SF 112 5.1 Iteration Cycle 113 5.1.1 Event Re-weighting 114 5.2 The Flux Measurement 115 5.2.1 Flux Extraction 118 5.3 SF Parameterization 127 6 Structure Function Extraction 136 6.1 Comparing the y-distributions 136 .. 6.1.1 The MC Simulated Events 137 6.1.2 Normalization 140 6.2 Minimizing X2 .•••...•••.•....•..•...••••..•.•..•••..........•..•••..••••.•••.•....•"...••.•.•••...•••. 143 6.2.1 The Minimization Software 143 6.2.2 Bin requirenlents 143 6.2.3 The Fit parameters 144 6.2.4 The Strange Sea 145 6.2.5 Three Parameter and Four Parameter fits 147 6.3 Systematic Errors 150 6.4 Testing the method 154 6.4.1 Fake Data Studies 154 6.4.2 Comparing to Previous CCFR Measurements 158 7 Results and Comparisons 163 - 7.1 RZong Measurements 164 7.2 K Results 169 7.3 F2 and xF3 measurements 172 - ii .. .. 7.4 Conclusions 178 Appendix A: Y Distributions Data Versus MC in (x,Q2) bins 181 - Appendix B: RZong Measurement and Error Table 192 Appendix C: Systematic Error Tables for RZong 195 Appendix D: F2 and xF3 Measurement and Error Table 199 Appendix E: Systematic Error Tables for F2 202 Appendix F: Systematic Error Tables for xF3 210 Appendix G: The Six Event Triggers 218 G.l Trigger 1: The Charged Current Trigger 218 G.2 Trigger 2: The Neutral Current Trigger 220 G.3 Trigger 3: The Muon Penetration Trigger 222 G.4 Trigger 4: Charged Current Efficiency Trigger 224 G.5 Trigger 5: Test Beam Trigger 225 G.6 Trigger 6: Straight Through Muon Trigger 225 Appendix H: Data versus MC Kinematic Comparison Plots 228 Appendix I: Systematic Error Tables for K 240 Appendix J: Source Code for SF Parameterization 242 - Bibliography 248 iii - List ofFigures Figure 1.1: A typical interaction between 2 elementary particles 5 Figure 1.2: Kinematic variables of deep-inelastic scattering 11 Figure 1.3: Possible helicity configurations for high-energy neutrinos and anti- neutrinos scattering from quarks and anti-quarks 19 Figure 1.5: Typical LO, NLO and NNLO QCD diagrams 26 Figure 1.6: Helicity configuration for the absorption of a boson by a s=1/2 parton. 28 Figure 1.7: Helicity configuration for the absorption of a boson by a s-O parton 29 - Figure 1.8: NLO QCD diagrams 30 Figure 2.1: Fermilab neutrino beamline layout. 38 Figure 2.2: Tevatron magnet current versus time during fixed-target operation 39 Figure 2.3: Neutrino Center beamline 41 Figure 2.4: Schematic representation of the CCFR detector 43 - Figure 2.5: A typical charged-current event as seen by the elements of the CCFR detector 44 Figure 2.6: Stack layout of a CCFR target cart 45 .... Figure 2.7: CCFR scintillation counter 46 Figure 2.8: Sketch of CCFR target drift chamber section 50 Figure 2.9: Schematic drawing of a CCFR toroid cart, showing overhead and - transverse views 52 Figure 2.10: Map of counters 57 Figure 2.11: Tube and counter configurations in the 2nd toroid gap 58 Figure 2.12: Counter and tube configuration in the 3rd toroid gap 59 Figure 2.13: Readout electronics for a single scintillation counter 61 Figure 3.1: Muon energy loss distribution in a scintillation counter 68 Figure 3.2: Contours of the relative muon response for counter 37 72 Figure 3.3: Energy response of the CCFR calorimeter, relating MIPs to GeV 75 Figure 3.4: Energy distributions of 25 and 200 GeV hadrons from the 1987 calibration 76 - Figure 3.5: The hadron shower energy resolution of the CCFR calorimeter from 25 to 240 GeV test beam calibrations 77 Figure 3.6: The E/p distribution for E744 range-out muons 79 Figure 3.7: Muon momentum resolution function for 120 GeV muons 87 Figure 4.1: Radiative-correction diagram from the muon leg 105 Figure 4.2: Radiative-correction diagram including the quark leg 105 Figure 5.1: Iteration cycle 113 Figure 5.2: Kinematic map showing the region where quasi-elastic processes - dominate the cross-section 122 - iv - Figure 5.3: The differential cross-section do/ dv in the low-y region for Ev == 60 GeV 123 - Figure 5.4: A typical fit for BfA to the dN f dv distribution 124 Figure 5.5: BfA as a function of energy for experiment E770 125 Figure 5.6: The correction due to BfA 126 Figure 5.7: The fully-corrected flux x energy spectra for E744 and E770 127 Figure 5.8: Final F2 measurements and SF parameterization #3 129 Figure 5.9: Final xF3 measurements (low x) with statistical errors and the SF parameterization #3 130 Figure 5.10: Final xF3 measurements (mid to high x) with statistical errors and the - SF parameterization #3 131 Figure 5.11: Final RZong measurements with statistical errors and the SF parameterization #3 132 Figure 6.1: LNG Strange Sea 147 Figure 6.2: K fit results in the first 5 x-bins 149 Figure 6.3: Global K result 150 Figure 6.4: Strange sea used in systematic error study 154 Figure 6.5: RZong results from fake data study 156 Figure 6.6: IhF3 results from fake data study 157 Figure 6.7: F2 results from 2 parameter fit. 160 Figure 6.8: xF3 results from 2 parameter fit.. 161 Figure 6.9: xF3 results from 2 parameter fit. 162 Figure 7.1: v and ;; y-distributions for (x==.045, Q2=5.l) 163 Figure 7.2: WorId R Zong measurements 165 Figure 7.3: Comparison of CCFR and NMC Rzong measurements .167 .- Figure 7.4: RZong predictions at low-x 169 Figure 7.5: New and previous CCFR F2 measurements 174 Figure 7.6: New and previous CCFR XF3 measurements (lst 5 x-bins) 175 - Figure 7.7: New and previous CCFR xF3 measurements (last 7 x-bins) 176 Figure 7.8: Ratio of new and old [SeI97] CCFR F2 177 Figure 7.9: Ratio of new and old [SeI97] CCFR xF3 178 Figure G.1: Trigger 1 Schematic 218 Figure G.2: Trigger 1 logic diagram 220 Figure G.3: Trigger 2 Schematic 221 Figure G.4: Trigger 2 logic diagram 222 Figure G.5: (Trigger 3) The penetration trigger signature 223 Figure G.6: Trigger 3 logic schematic 224 Figure G.7: Trigger 4 (the charged current efficiency trigger) logic 225 - Figure G.8: (Trigger 6) The straight through muon trigger 226 Figure G.9: Trigger 6 logic schematic 227 v - List ofTables Table 1.1: Interactions in the Standard Model 6 .

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