Elementary Particle Physics: An Intuitive Introduction

Half Title page
Title page
Copyright page
Dedication
Contents
Preface
	Overview of This Book
	Acknowledgements
1 Introduction
	1.1 A Brief History of Forces
	1.2 The Standard Model of Particle Physics
	1.3 The Large Hadron Collider
	1.4 Units of Particle Physics and Dimensional Analysis
	Exercises
2 Special Relativity
	2.1 Symmetries and Their Consequences
		2.1.1 Rotational Invariance
		2.1.2 Relativistic Invariance
		2.1.3 Applying Relativity
	2.2 Relativistic Wave Equations
		2.2.1 The Klein–Gordon Equation
		2.2.2 The Dirac Equation
		2.2.3 Electromagnetism
	Exercises
3 A Little Group Theory
	3.1 Groups as Symmetries
	3.2 The Rotation Group
		3.2.1 Two-Dimensional Rotations: SO(2)
		3.2.2 Three-Dimensional Rotations: SO(3)
		3.2.3 SO(3), SU(2), and Spin
	3.3 Isospin and the Quark Model
		3.3.1 Isospin
		3.3.2 What is a “Particle”?
		3.3.3 The Quark Model
	3.4 Why the Photon Has Two Polarizations
	Exercises
4 Fermi’s Golden Rule and Feynman Diagrams
	4.1 Invitation: The Barn
	4.2 Scattering Systematics
		4.2.1 The Scattering Cross Section
		4.2.2 Fermi’s Golden Rule
	4.3 Feynman Diagrams
		4.3.1 Diagrams in Physics: Circuits
		4.3.2 Diagrams in Physics: Electron–Muon Scattering
		4.3.3 Feynman Diagrams: Summary
		4.3.4 Feynman Diagrams: Caveat Emptor
	Exercises
5 Particle Collider Experiment
	5.1 Before Collision: Particle Acceleration
	5.2 At Collision: Particle Detection
	5.3 Detector Coordinates
	5.4 Detector Components
		5.4.1 Tracking System
		5.4.2 Calorimetry
		5.4.3 Muon System
		5.4.4 Unobservable Neutrinos
	5.5 After Collision: Triggering and Data Acquisition
	5.6 Statistical Analyses
		5.6.1 Statistical Uncertainties
		5.6.2 Derivation of Poisson Distribution
		5.6.3 Significance and Discovery
	Exercises
6 Quantum Electrodynamics in e+e− Collisions
	6.1 e+e− → μ+μ−
		6.1.1 Solutions to the Massless Dirac Equation
		6.1.2 Helicity Configurations
		6.1.3 Calculating the Cross Section
		6.1.4 Inclusive Cross Sections
		6.1.5 Exclusive Cross Sections
	6.2 e+e− → Hadrons
		6.2.1 Inclusive Hadronic Cross Sections
		6.2.2 Properties of the Inclusive Cross Section: Color
		6.2.3 Properties of the Inclusive Cross Section: Spin
	Exercises
7 Quarks and Gluons
	7.1 Crossing Symmetry
		7.1.1 Electron–Quark Scattering
	7.2 Deeply Inelastic Scattering
		7.2.1 Physical Interpretation of Bjorken Scaling
	7.3 Three-Jet Events
		7.3.1 The Glue That Binds the Proton
		7.3.2 External Gluon Wavefunction
		7.3.3 Fermion Propagator
		7.3.4 The Cross Section for e+e− → qqg
		7.3.5 Tests of a Spin-1 Gluon
	7.4 Spinor Helicity
	Exercises
8 Quantum Chromodynamics
	8.1 Color Symmetry
	8.2 Non-Abelian Gauge Theory
		8.2.1 Covariant Derivative
		8.2.2 Connections and Curvature
	8.3 Consequences of Quantum Chromodynamics
		8.3.1 Masslessness of the Gluon
		8.3.2 Gluon Degrees of Freedom
		8.3.3 Self-Interaction of the Gluon
		8.3.4 The Running Coupling and Asymptotic Freedom
		8.3.5 Low-Energy QCD
	Exercises
9 Parton Evolution and Jets
	9.1 Scale Transformations
		9.1.1 Scale Invariance of QCD
		9.1.2 Fractals and Scale Invariance
	9.2 Parton Evolution
		9.2.1 Collinear Divergences in QCD
		9.2.2 Energy Dependence of Parton Distributions
		9.2.3 Physical Interpretation of the DGLAP Equations
	9.3 Jets
		9.3.1 All-Orders Predictions: Thrust
	Exercises
10 Parity Violation
	10.1 Decay of the Neutron
	10.2 Discrete Lorentz Transformations
		10.2.1 Parity Transformations
		10.2.2 Time Reversal and Charge Conjugation
		10.2.3 CPT Theorem
	10.3 Parity Violation in Nuclear Decays
		10.3.1 Consequences of Parity Violation
	10.4 The V − A Theory
		10.4.1 Decay of the Muon
	Exercises
11 The Mass Scales of the Weak Force
	11.1 Problems with the V − A Theory
	11.2 Spontaneous Symmetry Breaking
		11.2.1 Quantum Mechanics Analogy
		11.2.2 Goldstone’s Theorem for the Mexican Hat Potential
		11.2.3 Higgs Mechanism in Superconductivity
	11.3 Electroweak Unification
		11.3.1 Properties of the Weak Force Carriers
		11.3.2 Spontaneous Breaking of Electroweak Symmetry
		11.3.3 The Broken Weak Theory
		11.3.4 Four Predictions of the Broken Weak Theory
	Exercises
12 Consequences of Weak Interactions
	12.1 Flavor Mixing in the Weak Interactions
	12.2 The Weak Interactions in the Quark Sector: CP Violation
		12.2.1 Weak Interactions of Charged Leptons
		12.2.2 Weak Interactions of Quarks
		12.2.3 CP Violation of the Weak Interactions
		12.2.4 Fermion Masses in the Standard Model and Tests of Unitarity
		12.2.5 CP Violation and the Early Universe: Sakharov Conditions
	12.3 The Weak Interactions in the Lepton Sector: Neutrino Mixing
		12.3.1 Neutrino Oscillations
		12.3.2 Neutrino Oscillation Measurement
		12.3.3 Neutrino Astrophysics
	Exercises
13 The Higgs Boson
	13.1 Searching for the Higgs Boson at LEP
		13.1.1 e+e− → Z
		13.1.2 e+e− → H
		13.1.3 e+e− → ZH
	13.2 Searching for the Higgs Boson at Tevatron and LHC
		13.2.1 pp → H
		13.2.2 pp → H → W+W−
		13.2.3 The Golden Channels: pp → H → γγ and pp → H → 4ℓ
	13.3 Properties of the Higgs Boson
		13.3.1 Scalar Potential Coupling λ
		13.3.2 Coupling Strength Proportional to Mass
		13.3.3 Spin-0
	Exercises
14 Particle Physics at the Frontier
	14.1 Neutrino Masses
	14.2 Dark Matter
	14.3 Higgs Self-Coupling
	14.4 End of Feynman Diagrams?
		14.4.1 Failure of Convergence of Feynman Diagrams
		14.4.2 More Efficient Calculational Techniques
	14.5 The Future of Collider Physics
		14.5.1 International Linear Collider (ILC)
		14.5.2 Circular Electron Positron Collider (CEPC)
		14.5.3 Future Circular Collider (FCC)
	Exercises
Appendix A Useful Identities
Appendix B Review of Quantum Mechanics
Appendix C Particle Physics Jargon Glossary
Bibliography
Index