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Searching for Slow-Developing Cosmic-Ray Showers: Looking for Evidence of Exotic Primaries at the Pierre Auger Observatory

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Searching for Slow-Developing Cosmic-Ray Showers: Looking for Evidence of Exotic Primaries at the Pierre Auger Observatory SEARCHING FOR SLOW-DEVELOPING COSMIC-RAY SHOWERS: LOOKING FOR EVIDENCE OF EXOTIC PRIMARIES AT THE PIERRE AUGER OBSERVATORY by Eric William Mayotte c Copyright by Eric William Mayotte, 2016 All Rights Reserved A thesis submitted to the Faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment of the requirements for the degree of Doctorate of Science (Applied Physics). Golden, Colorado Date Signed: Eric William Mayotte Signed: Dr. Frederic Sarazin Thesis Advisor Golden, Colorado Date Signed: Dr. Jeff Squier Professor and Head Department of Physics ii ABSTRACT The central purpose of this research was to add the event propagation velocity to the list of shower parameters that the Florescence Detector of Pierre Auger Observatory is capable of measuring. This capability was then leveraged to differentiate exotic slow moving events from the rest of the cosmic ray flux. Clearly, by relativistic necessity, all known cosmic ray primaries can only cause a measurable extensive air shower at velocities indistinguishably close to the speed of light. Therefore any accurate observation of an event propagating slower than the speed of light would provide an unmistakable indicator of new physics. A particle must possess very specific characteristics in order to be capable of producing a slow shower. High mass Strangelets, macroscopic dark matter, and super-symmetric Q- Balls were identified as strong candidates. Theory supporting high mass Strangelets and macroscopic dark matter appeared too late for full inclusion in this work, however super- symmetric Q-Balls were thoroughly examined. CORSIKA simulations were used to show that the fluorescence detector of the Pierre Auger Observatory has sensitivity to Q-Balls with a mass M > 3.25 1027GeV c−2 while the surface detector is sensitive at a mass Q × M > 1.15 1027GeV c−2. Q × The Pierre Auger Observatory was shown to be capable of accurately measuring a wide range of velocities with two independent methods. These methods were applied to 7 years of data and one candidate slow event was identified. This candidate measurement proved to be due to a rare and interesting, but ultimately, non-exotic effect, which when accounted for resulted in the event being measured normally. As a result of this, no exotic candidate events were found in the search. Recommendations are made for improving the result and promising alternative search methods are presented. iii TABLE OF CONTENTS ABSTRACT....................................................................................................iii LIST OF FIGURES.........................................................................................vii LIST OF TABLES..........................................................................................xiii LIST OF SYMBOLS....................................................................................... xiv LIST OF ABBREVIATIONS........................................................................... xvii ACKNOWLEDGMENTS................................................................................. xix DEDICATION................................................................................................xx CHAPTER 1 INTRODUCTION: EXOTIC ASTROPARTICLE PHYSICS..................1 CHAPTER 2 ULTRA-HIGH ENERGY COSMIC RAYS .........................................6 2.1 Cosmic Ray Spectrum ...................................................................7 2.2 Cosmic Ray Sources, Composition and Acceleration.............................8 2.3 The GZK and Ultra-High Energy Cosmic Rays................................. 12 2.4 Extensive Air Showers ................................................................. 16 CHAPTER 3 THE PIERRE AUGER OBSERVATORY........................................ 21 3.1 The Surface Detector................................................................... 22 3.2 The Fluorescence Detector............................................................ 27 3.3 FD-SD Cross Calibration ............................................................. 36 3.4 Atmospheric Monitoring............................................................... 38 3.4.1 The Geostationary Operational Environment Satellite............39 3.4.2 The Global Data Assimilation System................................. 40 iv 3.4.3 At Eye Atmospheric Monitoring Instruments........................ 41 3.4.4 Aerosol Monitoring and the Laser Facilities.......................... 42 3.5 FD Reconstruction...................................................................... 48 3.5.1 The Reconstruction of the Shower Detector Plane ................. 49 3.5.2 Monocular Axis Reconstruction ......................................... 51 3.5.3 Hybrid Reconstruction..................................................... 53 3.5.4 Stereo Axis Reconstruction............................................... 57 3.6 The Offline Framework ................................................................ 61 CHAPTER 4 EXOTIC SLOW EVENTS AND CANDIDATE PHENOMENA ........... 65 4.1 Candidate Particle Characteristics.................................................. 67 4.1.1 Q-Balls......................................................................... 69 4.1.2 CORSIKA Simulation of Q-Ball Showers ............................. 72 CHAPTER 5 THE VELOCITY SENSITIVITY OF THE PIERRE AUGER OBSERVATORY ........................................................................ 80 5.1 Simple Velocity Dependent Propagation Model with a Known Geometry 80 5.2 Velocity Sensitivity Range............................................................ 82 5.3 Atmospheric Corrections to the Velocity Dependent Propagation Model. 88 5.4 Laser Distributions and Interpretation ............................................ 95 5.5 The FD Velocity Sensitivity and Resolution ....................................108 CHAPTER 6 VELOCITY RECONSTRUCTION: STEREO OBSERVATIONS.........111 6.1 The Stereo Velocity Reconstruction...............................................111 6.2 StereoVelocityFinder Module........................................................114 6.3 Velocity Sensitivity Range...........................................................116 v 6.4 Laser Distributions and Interpretation ...........................................119 6.5 Data, Cuts and Final Distributions ...............................................120 6.5.1 Quality Cuts.................................................................123 6.5.2 Final Stereo Distribution.................................................128 CHAPTER 7 VELOCITY RECONSTRUCTION: HYBRID OBSERVATIONS .........130 7.1 Velocity Dependent Hybrid Reconstruction .....................................130 7.2 HybridVelocityFinder Module.......................................................136 7.3 Velocity Sensitivity Range...........................................................137 7.4 Laser Distributions and Interpretation ...........................................139 7.5 Data, Cuts and Final Distributions ...............................................141 7.5.1 Quality Cuts.................................................................143 7.5.2 Final Hybrid Distributions...............................................157 CHAPTER 8 CANDIDATE SELECTION AND ANALYSIS .................................160 8.1 Stereo Event Selection and Candidates...........................................162 8.2 Hybrid Event Selection and Candidates..........................................172 CHAPTER 9 CONCLUSIONS AND PERSPECTIVES........................................182 9.1 Research Summary ....................................................................182 9.2 Perspectives..............................................................................186 REFERENCES CITED ...................................................................................190 APPENDIX A - CRLF UPGRADE ...................................................................199 APPENDIX B - MAGNETIC MONOPOLES.......................................................212 APPENDIX C - HYBRID SELECTION PLOTS ..................................................216 APPENDIX D - SELECTED CANDIDATE EVENTS ...........................................221 vi LIST OF FIGURES Figure 2.1 The Latest Energy Spectrum of Cosmic Rays........................................9 Figure 2.2 The GZK Interaction..................................................................... 12 Figure 2.3 The GZK Suppression.................................................................... 13 Figure 2.4 Diagram of EAS Interactions........................................................... 16 Figure 2.5 A Simulated EAS Longitudinal Density Profile Fit by a Gaisser-Hillas ..... 18 Figure 2.6 Shower Front and Lateral Distribution Function.................................. 20 Figure 3.1 The Pierre Auger Observatory......................................................... 23 Figure 3.2 An Pierre Auger Observatory Surface Detector.................................... 24 Figure 3.3 The T3 SD Trigger........................................................................ 26 Figure 3.4 The Los Leones Detector . ............................................................. 27 Figure 3.5 Auger Fluorescence Telescope Schematic............................................ 28 Figure 3.6 FD Camera and Aperture............................................................... 30 Figure 3.7 Auger Fluorescence Telescope Electronics........................................... 31 Figure 3.8 T2 FD Trigger Minimum Pixel Geometries........................................
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