In the first fractions of a second after the Big Bang lingers a question at the heart of our very existence: why does the universe contain matter but almost no antimatter? The laws of physics tell us that equal amounts of matter and antimatter were produced in the early universe--but then something odd happened. Matter won out over antimatter; had it not, the universe today would be dark and barren. But how and when did this occur? In The Mystery of the Missing Antimatter, Helen Quinn and Yossi Nir guide readers into the very heart of this mystery--and along the way offer an exhilarating grand tour of cutting-edge physics.
Helen R. Quinn is professor emerita of particle physics and astrophysics at the Stanford Linear Accelerator Center at Stanford University. A member of the National Academy of Sciences, she is the coauthor of The Charm of Strange Quarks: Mysteries and Revolutions of Particle Physics. Yossi Nir is professor of physics at the Weizmann Institute of Science in Israel.
Acknowledgments xi Chapter 1: Prelude: The Mystery of the Missing Antimatter 1 Chapter 2: Constant Physics in an Evolving Universe 7 Universal Laws 7 Hubble and the Expanding Universe 8 Red-shifts: Evidence for an Expanding Universe 12 Numbers Large and Small 17 What Do We Mean by "Universe"? 19 Chapter 3: As the Universe Expands 21 Running the Clock Forward: Radiation 21 Running the Clock Forward: Dark Matter 26 Running the Clock Forward: Light Nuclei 29 Running the Clock Forward: Matter and Antimatter 32 Chapter 4: What Is Antimatter? 36 What Is Matter? 36 Dirac Introduces Antimatter 42 Experiments Confirm That Antimatter Exists 45 Radioactive Decays of Nuclei 48 Chapter 5: Enter Neutrinos 51 Pauli: The Beta Decay Puzzle 51 Fermi: The Theory of Neutrinos Develops 53 Cowan and Reines: Neutrinos Detected 55 Chapter 6: Mesons 57 Yukawa and the Pi-Meson 57 Strange Mesons, Strange Quantum Concepts 61 Chapter 7: Through the Looking Glass 63 What Physicists Mean by the Term Symmetry 63 A Gedanken Experiment 64 The Actual Experiment 67 Chapter 8: Through the Looking Antiglass 73 Another Gedanken Experiment 73 Cronin and Fitch: Matter and Antimatter Do Not Follow the Same Laws 75 Chapter 9: The Survival of Matter 80 Pauli's Other Letter: Initial Conditions on the Universe 80 Sakharov: The Conditions Needed to Develop an Imbalance 84 Cosmology with Sakharov's Conditions Met: Baryogenesis 88 Chapter 10: Enter Quarks 91 Quarks 91 Why Don't We See the Quarks? 96 What about Dark Matter? 100 The Missing Charm, the Surprising Tau 101 The Standard Model: Particles and Interactions 107 Chapter 11: Energy Rules 111 Stored Energy, Forces, and Energy Conservation 111 Force Fields Permeating Space 114 Field Theory and the Energy Function 116 Chapter 12: Symmetry Rules 121 Symmetries as Answers to the Question "Why?" 121 Symmetries and Conservation Laws 123 Space-Time Symmetries 124 Gauge Symmetries 126 Discrete Symmetries 128 Baryon and Lepton Number Conservation? 130 Chapter 13: Standard Model Gauge Symmetries 132 The Symmetry behind the Electromagnetic Interaction 132 The Symmetry behind the Strong Interaction 134 The Symmetry behind the Weak Interaction 137 Chapter 14: A Missing Piece 140 The Puzzle of Particle Masses 140 How Do We Describe Nothing? 146 At Last, CP Violated in the Standard Model 153 Chapter 15: It Still Doesn't Work! 159 Running the Clock Forward: The Standard Model 159 Now What? 163 Chapter 16: Tools of the Trade 168 Accelerators 168 Detectors 172 Data Handling and Analysis 177 How Projects Develop 178 Chapter 17: Searching for Clues 180 Where Are We Now? 180 Testing the Standard Model in B-Meson Decays 182 Oddone: How to Build B Factories? 184 Running the B Factories: The First Test 190 Chapter 18: Speculations 194 Why Are We Never Satisfied? 194 Grand Unified Theories 195 Supersymmetry 201 Way beyond the Standard Model 204 Chapter 19: Neutrino Surprises 206 Davis, Bahcall, Koshiba: Solar Neutrinos 206 Quantum Neutrino Properties 214 Chapter 20: Following the New Clues 222 Some Things We Know 222 Some Things We Speculate About 225 Fitting It All Together 227 Chapter 21: Finale 231 Appendix: A Timeline of Particle Physics and Cosmology 233 Perspective 233 Relevant Nineteenth-Century Developments 234 1900-1930: Development of Quantum Ideas, Beginnings of Scientific Cosmology 238 1930-1950: New Particles, New Ideas 245 1930-1960s: The Advent of Accelerator Experiments--The Particle Explosion; Implications of Expanding Universe Explored 249 1964-1973: Formulation of the Modern View of Particles and the Universe 256 Two Standard Models Emerge--Particles and Cosmology 263 Index 273