Perturbative QCD

The following sections are included:

• FOREWORD

• CONTENTS

We summarize the standard factorization theorems for hard processes in QCD, and describe their proofs.

The following sections are included:

• INTRODUCTION

• NONRELATIVISTIC FORM FACTORS FOR HEAVY-QUARK MESONS

• HADRONIC WAVEFUNCTIONS
  • DEFINITIONS
  • LIGHT-CONE BOUND-STATE EQUATIONS
  • GENERAL PROPERTIES OF LIGHT-CONE WAVEFUNCTIONS
  • RENORMALIZATION
  • CALCULATING

• A PERTURBATIVE ANALYSIS
  • FACTORIZATION—LEADING ORDER ANALYSIS
  • THE QUARK DISTRIBUTION AMPLITUDE
  • DETERMINATION OF DISTRIBUTION AMPLITUDES
  • HIGHER ORDER ANALYSIS
  • COMPLICATIONS
  • How LARGE IS ASYMPTOTIC Q?

• APPLICATIONS OF QCD TO THE PHENOMENOLOGY OF EXCLUSIVE REACTIONS
  • GENERAL FEATURES OF EXCLUSIVE PROCESSES IN QCD
  • ELECTROMAGNETIC FORM FACTORS
  • COMPARISON OF QCD SCALING WITH EXPERIMENT
  • EXCLUSIVE ANTI-PROTON PROTON ANNIHILATION PROCESSES
  • ADDITIONAL TESTS OF GLUON SPIN IN EXCLUSIVE PROCESSES
  • HADRONIC WAVEFUNCTION PHENOMENOLOGY
  • CALCULATING T_H
  • THE PRE-QCD DEVELOPMENT OF EXCLUSIVE REACTIONS

• EXCLUSIVE e⁺ e⁻ ANNIHILATION PROCESSES
  • J/ψ DECAY TO HADRON PAIRS
  • THE π-ρ PUZZLE
  • FORM FACTOR ZEROS IN QCD

• EXCLUSIVE γγ REACTIONS

• QCD PROCESSES IN NUCLEI
  • EXCLUSIVE NUCLEAR REACTIONS – REDUCED AMPLITUDES
  • COLOR TRANSPARENCY

• SPIN CORRELATIONS IN PROTON-PROTON SCATTERING

• CONCLUSIONS

• APPENDIX I BARYON FORM FACTORS AND EVOLUTION EQUATIONS

• APPENDIX II LIGHT CONE QUANTIZATION AND PERTURBATION THEORY

• APPENDIX III A NONPERTURBATIVE ANALYSIS OF EXCLUSIVE REACTIONS-DISCRETIZED LIGHT-CONE QUANTIZATION

• ACKNOWLEDGEMENTS

• REFERENCES

This paper presents a review of analytical perturbative approach to QCD jet physics. The role of coherent phenomena reflecting the collective character of multiple hadroproduction is emphasized. The following sections are included:

• INTRODUCTION
  • Perturbative Approach to Hard Processes and Jets
  • Petrurbation Theory and Shower Picture
  • Leading Logs, Coherence and Hadronization Schemes

• SPACE-TIME PICTURE OF QCD BREMSSTRAHLUNG AND LOCAL PARTON-HADRON DUALITY
  • Radiation of Partons
  • Formation and Hadronization times
  • Gluons and ‘Gluers’s Soft Confinement Scenario
  • Angular Ordering and ‘Partonic Gas’
  • LPHD Concept

• ESSENCE OF QCD COHERENCE
  • Angular Ordering of Successive Parton Branching
  • Hump-Backed QCD Plateau in Particle Spectra
  • Soft Gluon Emission from Colourless ‘Quark-Antiquark Antenna’
  • Physical Origin of Drag Effect

• DOUBLE LOG APPROXIMATION
  • Tree Multigluon Amplitudes for
  • Proof of Angular Ordering
  • Virtual Corrections
  • Cross Section. Method of Generating Functionals
  • Multiplicity Distributions in DLA
  • Inclusive Particle Spectra in DLA
  • ζ -Scaling

• MODIFIED LEADING LOG APPROXIMATION
  • Exact Angular Ordering
  • MLLA Master Equation
  • V-Scheme for Gluon Cascades
  • Jet Polarizability arid Colour Monsters
  • Magnitude of Dipole Corrections to Jet Characteristics

• MLLA RESULTS FOR JET CHARACTERISTICS
  • Correlators of Jet Multiplicity
  • Inclusive Energy Spectrum of Partons in MLLA
  • Developed Cascade and LPHD Concept
  • On Infrared Stability of Limiting Parton Spectrum

• CHROMODYNAMICS OF HADRONIC JETS
  • On Experimental Selection Procedures
  • On Structure of Particle Flows in Multijet Events
  • QCD Portrait of Individual Jet

• RADIOPHYSICS OF PARTICLE FLOWS
  • Inclusive QCD Portrait of Events of e⁺e⁻ Annihilation
  • Drag Phenomena in High p_⊥ Hadronic Reactions
  • Prompt & Production at Large p_⊥
  • Two Jet Production at Large p_⊥
  • Correlations of Interjet Particle Flows
  • Azimuthal Asymmetry of QCD Jets

• COHERENCE AND FINAL FINAL STATES IN DEEPLY INELASTIC SCATTERING
  • The Structure of Soft Radiation Associated with DIS
  • Angular Ordering for Space-Like Cascades
  • The Structure of Inclusive Spectrum in Target Fragmentation
  • On the QCD Solution of Feynman-Gribov Puzzle

• CONCLUSIONS

• ACKNOWLEDGEMENTS

• REFERENCES

Various approaches to the investigation of the high energy asymptotics of scattering amplitudes in QCD are reviewed. We begin with the approximation of the two gluon exchange. Then quark scattering amplitudes with the elastic and quasielastic unitarity are constructed. The inelastic amplitude for production of gluons in the multi-Regge kinematics is obtained in the leading logarithmic approximation. The bare pomeron trajectory is calculated at large momentum transfers. In conclusion the problem of unitarization of the scattering amplitudes is discussed. The following sections are included:

• INTRODUCTION

• HADRON SCATTERING AMPLITUDES IN THE BORN APPROXIMATION

• QUARK SCATTERING AMPLITUDES WITH QUASI-ELASTIC UNITARITY

• LEADING LOGARITHMIC APPROXIMATION FOR INELASTIC AMPLITUDES

• THE INTEGRAL EQUATION FOR VACUUM CHANNEL PARTIAL WAVES

• CONFORMAL INVARIANCE AND PARAMETERS OF BARE REGGEONS

• CONCLUSION

• Appendix I

• Appendix II

• References

The following sections are included:

• INTRODUCTION AND GENERAL FEATURES
  • Motivation
  • The Method of Asymptotic Dynamics
  • Infrared and Collinear Singularities. The KLN Theorem
  • Coherent States
  • Outline

• QUANTUM ELECTRODYNAMICS
  • Asymptotic Hamiltonian
  • Energy Transfer Evolution Equations
  • Coherent states and Soft Radiation Properties
  • Angular Dependence and Coherence Patterns

• QUANTUM CHROMODYNAMICS
  • Asymptotic Hamiltonian and Eikonal Vertices
  • Leading Singularities in Perturbation Theory
  • Leading Coherent State Operator
  • The Non-abelian Coulomb phase
  • Subleading Bloch-Nordsieck Violating Terms and Confinement

• THE PHYSICS OF SOFT GLUON EMISSION
  • QCD Form Factors
  • Coherence Effects and Angular Ordering
  • Gluon and Hadron Multiplicity Distributions

• OUTLOOK

• Acknowledgements

• REFERENCES

• FIGURE CAPTIONS

The theory of the on-shell Sudakov form factor to all order of logarithms is explained.