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ELECTROMAGNETIC INTERACTIONS AND
HADRONIC STRUCTURE
Thenucleiofatomsareconstructedfromprotonsandneutronsthat,inturn,arecon-
structedfrommorefundamentalparticles:quarks.Thedistributionofquarkswithin
protonsandneutrons,theirinteractions,andhowtheydefinethepropertiesofpro-
tonsandneutrons,andhencenuclei,aresubjectsofmajorresearchworldwide.This
studyrequirestheuseofbeamsofhigh-energyelectrons.Understandingofproton
structure at high energies has been greatly expanded by the study of generalized
partondistributionsandofnucleonspinstructure.Photonscanseparatetherolesof
quarkandgluonicdegreesoffreedomwithinhadronsandhencefilterglueballsand
hybridmesons.Athighenergies,bothphotonandnucleonstructurecanbeprobed.
Theformermanifestsitselfindiffractivephotoprocesses,wherethereisauniquely
rich interplay between perturbative and non-perturbative effects. This book pro-
videsanauthoritativeoverviewonthesubject,andsectionsonchiralperturbation
theory, crucial in understanding soft pions and soft photons near threshold, and
dualityideas,equallycrucialatintermediateenergies,areincluded.
Theemphasisthroughoutthebookisonphenomenology,andthebookconcentrates
on describing the main features of the experimental data and the theoretical ideas
usedintheirinterpretation.Writtenbyleadingexpertsinthefield,boththeoretical
andexperimental,thisisanessentialreferenceforgraduatestudentsandresearchers
inthefieldofparticlephysicsandelectromagneticinteractions.
Frank Close isProfessorofPhysicsattheRudolphPeierlsCentreforTheoret-
icalPhysics,OxfordUniversity.HegainedaD.PhilatOxfordUniversity,andhas
workedatStanfordLinearAcceleratorCenter(SLAC),CERN,andtheRutherford
AppletonLaboratory.ProfessorClosehasbeenawardedtheKelvinMedalfromthe
Institute of Physics and is the author of many books aimed at both a professional
andalayaudience,mostrecentlyTheNewCosmicOnion(Taylor&Francis,2006).
Sandy Donnachie isHonoraryResearchProfessorintheSchoolofPhysics
andAstronomyattheUniversityofManchester.SincegaininghisPh.D.fromthe
University of Glasgow, Professor Donnachie has held positions at the University
CollegeLondon,CERN,theUniversityofGlasgowandDaresburyNationalLab-
oratory. He was awarded the Glazebrook Medal from the Institute of Physics and
wasco-authorofPomeronPhysicsandQCD(CambridgeUniversityPress2002).
Graham Shaw isaseniorlecturerintheSchoolofPhysicsandAstronomyatthe
UniversityofManchester.HegainedhisPh.D.fromtheUniversityofLondon.He
hasheldpositionsattheRutherfordLaboratory,DaresburyNationalLaboratoryand
Columbia University. His many books include the well-known texts on Quantum
FieldTheoryandParticlePhysics(Wiley,latesteditions1993and1997).
CAMBRIDGE MONOGRAPHS ON
PARTICLE PHYSICS
NUCLEAR PHYSICS AND COSMOLOGY 25
GeneralEditors:T.Ericson,P.V.Landshoff
1. K.Winter(ed.):NeutrinoPhysics
2. J.F.Donoghue,E.GolowichandB.R.Holstein:DynamicsoftheStandardModel
3. E. Leader and E. Predazzi: An Introduction to Gauge Theories and Modern Particle Physics, Volume 1:
ElectroweakInteractions,the‘NewParticles’andthePartonModel
4. E. Leader and E. Predazzi: An Introduction to Gauge Theories and Modern Particle Physics, Volume 2:
CP-Violation,QCDandHardProcesses
5. C.Grupen:ParticleDetectors
6. H.GrosseandA.Martin:ParticlePhysicsandtheSchro¨dingerEquation
7. B.Anderson:TheLundModel
8. R.K.Ellis,W.J.StirlingandB.R.Webber:QCDandColliderPhysics
9. I.I.BigiandA.I.Sanda:CPViolation
10. A.V.ManoharandM.B.Wise:HeavyQuarkPhysics
11. R.K.Bock,H.Grote,R.Fru¨hwirthandM.Regler:DataAnalysisTechniquesforHigh-EnergyPhysics,Second
edition
12. D.Green:ThePhysicsofParticleDetectors
13. V.N.GribovandJ.Nyiri:QuantumElectrodynamics
14. K.Winter(ed.):NeutrinoPhysics,Secondedition
15. E.Leader:SpininParticlePhysics
16. J.D.Walecka:ElectronScatteringforNuclearandNucleonStructure
17. S.Narison:QCDasaTheoryofHadrons
18. J.F.LetessierandJ.Rafelski:HadronsandQuark–GluonPlasma
19. A.Donnachie,H.G.Dosch,P.V.LandshoffandO.Nachtmann:PomeronPhysicsandQCD
20. A.Hofmann:ThePhysicsofSynchrotronRadiation
21. J.B.KogutandM.A.Stephanov:ThePhasesofQuantumChromodynamics
22. D.Green:HighPT PhysicsatHadronColliders
23. K.Yagi,T.HatsudaandY.Miake:Quark–GluonPlasma
24. D.M.BrinkandR.A.Broglia:NuclearSuperfluidity
25. F.E.Close,A.DonnachieandG.Shaw:ElectromagneticInteractionsandHadronicStructure
ELECTROMAGNETIC INTERACTIONS
AND HADRONIC STRUCTURE
Editedby
FRANK CLOSE
UniversityofOxford,UK
SANDY DONNACHIE
UniversityofManchester,UK
GRAHAM SHAW
UniversityofManchester,UK
CAMBRIDGEUNIVERSITY PRESS
Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo
Cambridge University Press
The Edinburgh Building, Cambridge CB2 8RU, UK
Published in the United States of America by Cambridge University Press, New York
www.cambridge.org
Information on this title: www.cambridge.org/9780521844208
© Cambridge University Press 2007
This publication is in copyright. Subject to statutory exception and to the provision of
relevant collective licensing agreements, no reproduction of any part may take place
without the written permission of Cambridge University Press.
First published in print format 2007
ISBN-13 978-0-511-28521-9 eBook (EBL)
ISBN-10 0-511-28521-3 eBook (EBL)
ISBN-13 978-0-521-84420-8 hardback
ISBN-10 0-521-84420-7 hardback
Cambridge University Press has no responsibility for the persistence or accuracy of urls
for external or third-party internet websites referred to in this publication, and does not
guarantee that any content on such websites is, or will remain, accurate or appropriate.
Contents
Listofcontributors pagexi
Preface xii
1 Quarkmodelsofhadronsandissuesinquarkdynamics 1
1.1 Chromostatics 1
1.2 Mesonsasboundstatesfrombb¯ tolightflavours 3
1.3 Flavourmixings 7
1.4 Baryons 13
1.5 Spin–flavourcorrelations 15
1.6 SU(6)multipletsandexcitedmultiplets 17
1.7 Roleof Q2asatestofdynamics 20
1.8 Pentaquarksandexoticbaryons 24
1.9 Gluonicexcitations 28
References 36
2 Elasticformfactors 39
2.1 Electronscatteringandform-factormeasurements 40
2.2 Space-likenucleonformfactors 42
2.3 Modelcalculationsofnucleonformfactors 52
2.4 Time-likenucleonformfactors 55
2.5 Thepionformfactor 57
2.6 Theaxialformfactor 63
2.7 Nucleonstrangeformfactors 66
2.8 Outlookandconclusions 71
References 72
3 Electromagneticexcitationsofnucleonresonances 77
3.1 Issues 77
3.2 Generalformalism 80
vii
viii Contents
3.3 Theoreticalmodels 85
3.4 Dataandresults 100
3.5 Concludingremarksandoutlook 130
References 131
4 Mesonradiativedecays 137
4.1 Electron–positronannihilationandτ decay 137
4.2 Single-photontransitionsbetweenmesons 151
4.3 Two-photondecaysofmesons 167
References 178
5 Intermediate-energyphotoproduction 182
5.1 Reggepoles 183
5.2 Photoproductionofpseudoscalarmesons 196
5.3 Vector-mesonphotoproduction 211
5.4 Exoticmesons 224
References 225
6 Chiralperturbationtheory 229
6.1 Chiralsymmetry 230
6.2 EffectivefieldtheoryofGoldstonebosons 236
6.3 Mesonicchiralperturbationtheory 238
6.4 Includingnucleons 250
References 268
7 Spinstructurefunctions 271
7.1 Leptoproduction 271
7.2 Structurefunctionsandcrosssection 274
7.3 Virtualphotoncrosssections 277
7.4 Symmetrypropertiesofthestructurefunctions 278
7.5 Polarizedleptoproduction 279
7.6 Thepartonmodel 281
7.7 Propertiesofquarkdistributions 286
7.8 QCDcorrectionsindeepinelasticscattering 293
7.9 Evolutionequations 293
7.10 One-particleinclusiveleptoproduction 298
7.11 Collinearpartondistributions 301
7.12 Boundsonthedistributionfunctions 303
7.13 Transversemomentum-dependentcorrelationfunctions 305
7.14 Fragmentationfunctions 307
