《Quarks and leptons an introductory course in modern particle physics》

1A Preview of Particle Physics1

1.1 What is the World Made of？，1

1.2 Quarks and Color，4

1.3 Color： The Charge of Nuclear Interactions，7

1.4 Natural Units，12

1.5 Alpha （α） is not the Only Charge Associated with Particle Interactions，14

1.6 There Are Weak Interactions， Too，21

1.7 Down Mendeleev’s Path： More Quarks and Leptons，26

1.8 Gravity，27

1.9 Particles： The Experimentalist’s Point of View，28

1.10 Particle Detectors，30

2Symmetries and Quarks33

Symmetries and Groups33

2.1 Symmetries in Physics： An Example，33

2.2 Symmetries and Groups： A Brief Introduction，35

2.3 The Group SU（2），39

2.4 Combining Representations，40

2.5 Finite Symmetry Groups： P and C，41

2.6 SU（2） of Isospin，41

2.7 Isospin for Antiparticles，42

2.8 The Group SU（3），43

2.9 Another Example of an SU（3） Group： Isospin and Strangeness，44

Quark “Atoms”46

2.10 Quark- Antiquark States： Mesons，46

2.11 Three-Quark States： Baryons，50

2.12 Magnetic Moments，55

2.13 Heavy Quarks： Charm and Beyond，57

2.14 Hadron Masses，63

2.15 Color Factors，67

3 Antiparticles70

3.1 Nonrelativistic Quantum Mechanics，71

3.2 Lorentz Covariance and Four-Vector Notation，72

3.3 The Klein-Gordon Equation，74

3.4 Historical Interlude，75

3.5 The Feynman-Stuckelberg Interpretation of E < 0 Solutions，77

3.6 Nonrelativistic Perturbation Theory，79

3.7 Rules for Scattering Amplitudes in the Feynman-Stuckelberg Approach，82

4 Electrodynamics of Spinless Particles84

4.1 An “Electron” in an Electromagnetic Field Aμ，84

4.2 “Spinless” Electron-Muon Scattering，86

4.3 The Cross Section in Terms of the Invariant Amplitude ？，88

4.4 The Decay Rate in Terms of ？92

4.5 “Spinless” Electron-Electron Scattering，92

4.6 Electron- Positron Scattering： An Application of Crossing，93

4.7 Invariant Variables，94

4.8 The Origin of the Propagator，97

4.9 Summary，99

5The Dirac Equation100

5.1 Covariant Form of the Dirac Equation. Dirac γ-Matrices，102

5.2 Conserved Current and the Adjoint Equation，103

5.3 Free-Particle Spinors，104

5.4 Antiparticles，107

5.5 Normalization of Spinors and the Completeness Relations，110

5.6 Bilinear Covariants，111

5.7 Zero-Mass FermionsThe Two-Component Neutrino，114

6Electrodynamics of Spin-1/2 Particles117

6.1 An Electron Interacting with an Electromagnetic Field Aμ，117

6.2 Moller Scattering e- e- → e- e-，119

6.3 The Process e- μ- →’ e- μ- ，121

6.4 Trace Theorems and Properties of γ-Matrices，123

6.5 e- μ- Scattering and the Process e＋ e- → μ＋ μ-，123

6.6 Helicity Conservation at High Energies，126

6.7 Survey of e-e＋ →e- e＋， μ- μ＋，129

6.8 e- μ- → e- μ- in the Laboratory Frame. Kinematics Relevant to the Parton Model，130

6.9 Photons. Polarization Vectors，132

6.10 More on Propagators. The Electron Propagator，135

6.11 The Photon Propagator，137

6.12 Massive Vector Particles，138

6.13 Real and Virtual Photons，139

6.14 Compton Scattering γe-→ γe-，141

6.15 Pair Annihilation e＋ e- → γγ144

6.16 The ＋ iε Prescription for Propagators，145

6.17 Summary of the Feynman Rules for QED，150

7 Loops， Renormalization， Running Coupling Constants，and All That152

7.1 Scattering Electrons Off a Static Charge，152

7.2 Higher-Order Corrections，154

7.3 The Lamb Shift158

7.4 More Loops： The Anomalous Magnetic Moment，159

7.5 Putting the Loops Together： Ward Identities，162

7.6 Charge Screening and e-μ- Scattering，163

7.7 Renormalization，163

7.8 Charge Screening in QED： The Running Coupling Constant，167

7.9 Running Coupling Constant for QCD，169

7.10 Summary and Comments，171

8The Structure of Hadrons172

8.1 Probing a Charge Distribution with Electrons. Form Factors，172

8.2 Electron-Proton ScatteringProton Form Factors，175

8.3 Inelastic Electron-Proton Scattering ep → eX，179

8.4 Summary of the Formalism for Analyzing ep Scattering，183

8.5 Inelastic Electron Scattering as a （Virtual） Photon-Proton Total Cross Section，184

9 Partons188

9.1 Bjorken Scaling，188

9.2 Partons and Bjorken Scaling，191

9.3 The Quarks Within the Proton，196

9.4 Where Are the Gluons？，202

10 Quantum Chromodynamics205

10.1 The Dual Role of Gluons，205

10.2 Embedding γ＊-Parton Processes in Deep Inelastic Scattering，208

10.3 The Parton Model Revisited，209

10.4 The Gluon Emission Cross Section，210

10.5 Scaling Violations. The Altarelli-Parisi Equation，215

10.6 Including Gluon Pair Production，219

10.7 Complete Evolution Equations for the Parton Densities，220

10.8 Physical Interpretation of the P Functions，221

10.9 The Altarelli-Parisi Techniques Also Apply to Leptons and Photons： The Weizsacker-Williams Formula，224

11e ＋ e - Annihilation and QCD226

11.1 e-e＋ Annihilation Into Hadrons： e-e＋→ qq-，226

11.2 Fragmentation Functions and Their Scaling Properties，230

11.3 A Comment on Heavy Quark Production，234

11.4 Three-Jet Events： e-e＋→ qq-g，234

11.5 An Alternative Derivation of the e-e＋→ qq-g Cross Section，238

11.6 A Discussion of Three-Jet Events，240

11.7 QCD Corrections to e-e＋→ Hadrons，243

11.8 Perturbative QCD，245

11.9 A Final Example： The Drell-Yan Process，247

12Weak Interactions251

12.1 Parity Violation and the V-A Form of the Weak Current，252

12.2 Interpretation of the Coupling G，256

12.3 Nuclear β-Decay，258

12.4 Further Trace Theorems，261

12.5 Muon Decay，261

12.6 Pion Decay，264

12.7 Charged Current Neutrino-Electron Scattering，267

12.8 Neutrino-Quark Scattering，271

12.9 First Observation of Weak Neutral Currents，276

12.10 Neutral Current Neutrino-Quark Scattering，277

12.11 The Cabibbo Angle，279

12.12 Weak Mixing Angles，283

12.13 CP Invariance？，287

12.14 CP Violation： The Neutral Kaon System，289

13Electroweak Interactions292

13.1 Weak Isospin and Hypercharge，292

13.2 The Basic Electroweak Interaction，295

13.3 The Effective Current-Current Interaction，298

13.4 Feynman Rules for Electroweak Interactions，299

13.5 Neutrino-Electron Scattering，302

13.6 Electroweak Interference in e＋e Annihilation，305

13.7 Other Observable Electroweak Interference Effects，308

14Gauge Symmetries311

14.1 The Lagrangian and Single-Particle Wave Equations，311

14.2 Noether s Theorem： Symmetries and C onscrvation Laws，314

14.3 U（1） Local Gauge Invariance and QED，316

14.4 Non-Abelian Gauge Invariance and QCD，317

14.5 Massive Gauge Bosons？，320

14.6 Spontaneous Symmetry Breaking： “Hidden” Symmetry，321

14.7 Spontaneous Breaking of a Global Gauge Symmetry，324

14.8 The Higgs Mechanism，326

14.9 Spontaneous Breaking of a Local SU（2） Gauge Symmetry，327

15The Weinberg-Salam Model and Beyond331

15.1 Electroweak Interactions Revisited，331

15.2 Choice of the Higgs Field，334

15.3 Masses of the Gauge Bosons，335

15.4 Masses of the Fermions，338

15.5 The Standard Model： The Final Lagrangian，341

15.6 Electroweak Theory is Renormalizable，342

15.7 Grand Unification，344

15.8 Can the Proton Decay？，349

15.9 The Early Universe as a High-Energy Physics Experiment，352

15.10 “Grander” Unification？，354

Answers and Comments on the Exercises355

Supplementary Reading377

References381

Index385