ParticlesandNuclei An Introduction to the Physical Concepts Bogdan Povh Klaus Rith Christoph Scholz Frank Zetsche Particles and Nuclei An Introduction to the Physical Concepts TranslatedbyMartinLavelle FifthEdition With148Figures,11Tables,and58ProblemsandSolutions 123 ProfessorDr.BogdanPovh ProfessorDr.KlausRith Max-Planck-InstitutfürKernphysik PhysikalischesInstitut Postfach103980 derUniversitätErlangen-Nürnberg 69029Heidelberg,Germany Erwin-Rommel-Strasse1 91058Erlangen,Germany Dr.ChristophScholz Dr.FrankZetsche SAPAG UniversitätHamburgund Postfach1461 DeutschesElektronen-Synchrotron 69185Walldorf,Germany Notkestrasse85 22603Hamburg,Germany Translator: Dr.MartinLavelle InstitutdeFísicad’AltesEnergies FacultatdeCiències UniversitatAutònomadeBarcelona 08193Bellaterra(Barcelona),Spain TitleoftheoriginalGermanEdition: B.Povh,K.Rith,C.Scholz,F.Zetsche:TeilchenundKerne EineEinführungindiephysikalischenKonzepte. (7.Auflage) ©Springer1993,1994,1995,1997,1999,2004und2006 LibraryofCongressControlNumber:2006932338 ISBN-10 3-540-36683-0 5thEditionSpringerBerlinHeidelbergNewYork ISBN-13 978-3-540-36683-6 5thEditionSpringerBerlinHeidelbergNewYork ISBN 3-540-20168-8 4thEditionSpringerBerlinHeidelbergNewYork Thisworkissubjecttocopyright.Allrightsarereserved,whetherthewholeorpartofthematerialisconcerned, specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation,broadcasting,reproduction onmicrofilmorinanyotherway,andstorageindatabanks.Duplicationofthispublicationorpartsthereofis permittedonlyundertheprovisionsoftheGermanCopyrightLawofSeptember9,1965,initscurrentversion, andpermissionforusemustalwaysbeobtainedfromSpringer.Violationsareliableforprosecutionunder theGermanCopyrightLaw. SpringerisapartofSpringerScience+BusinessMedia springer.com ©Springer-VerlagBerlinHeidelberg1995,1999,2002,2004,2006 Theuseofgeneraldescriptivenames,registerednames,trademarks,etc.inthispublicationdoesnotimply, evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevantprotectivelawsand regulationsandthereforefreeforgeneraluse. Typesetting:JürgenSawinski,Heidelberg Production:LE-TEXJelonek,Schmidt&VöcklerGbR,Leipzig Cover:WMXDesignGmbH,Heidelberg SPIN11801610 56/3100YL-543210 Printedonacid-freepaper Preface In the last two editions we included new results on the neutrino oscillations as evidence for a non-vanishing mass of the neutrinos. In the present edition we have rewritten the chapter on “Phenomenology oftheWeakInteraction”(Chapter10)inordertogiveacoherentpresentation oftheneutrinoproperties.Furthermore,weextendedthechapteron“Nuclear Thermodynamics” (Chapter 19). Heidelberg, July 2006 Bogdan Povh Preface to the First Edition The aim of Particles and Nuclei is to give a unified description of nuclear and particle physics because the experiments which have uncovered thesubstructureofatomicnucleiandnucleonsareconceptuallysimilar.With theprogressofexperimentalandtheoreticalmethods,atoms,nuclei,nucleons, and finally quarks have been analysed during the course of this century. The intuitive assumption that our world is composed of a few constituents — an idea which seems attractive, but could not be taken for granted — appears to be confirmed. Moreover, the interactions between these constituents of matter can be formulated elegantly, and are well understood conceptionally, within the so-called “standard model”. Once we have arrived at this underlying theory we are immediately faced withthequestionofhowthecomplexstructuresaroundusareproducedbyit. Onthewayfromelementaryparticlestonucleonsandnucleiwelearnthatthe “fundamental” laws of the interaction between elementary particles are less and less recognisable in composite systems because many-body interactions cause greater and greater complexity for larger systems. This book is therefore divided into two parts. In the first part we deal with the reduction of matter in all its complication to a few elementary con- stituentsandinteractions,whilethesecondpartisdevotedtothecomposition of hadrons and nuclei from their constituents. We put special emphasis on the description of the experimental concepts but we mostly refrain from explaining technical details. The appendix con- tains a short description of the principles of accelerators and detectors. The exercises predominantly aim at giving the students a feeling for the sizes of the phenomena of nuclear and particle physics. Whereverpossible,werefertothesimilaritiesbetweenatoms,nuclei,and hadrons, because applying analogies has not only turned out to be a very effectiveresearchtoolbutisalsoveryhelpfulforunderstandingthecharacter of the underlying physics. We have aimed at a concise description but have taken care that all the fundamental concepts are clearly described. Regarding our selection of top- ics, we were guided by pedagogical considerations. This is why we describe experiments which — from today’s point of view — can be interpreted in a straightforwardway.Manyhistoricallysignificantexperiments,whoseresults can nowadays be much more simply obtained, were deliberately omitted. Particles and Nuclei(Teilchen und Kerne)isbasedonlectureson nuclearandparticlephysicsgivenattheUniversityofHeidelbergtostudents in their 6th semester and conveys the fundamental knowledge in this area, which is required of a student majoring in physics. On traditional grounds these lectures, and therefore this book, strongly emphasise the physical con- cepts. We are particularly grateful to J. Hu¨fner (Heidelberg) and M. Rosina (Ljubljana)fortheirvaluablecontributionstothenuclearphysicspartofthe book.WewouldliketothankD.Dubbers(Heidelberg),A.Fa¨ßler(Tu¨bingen), G. Garvey (Los Alamos), H. Koch (Bochum), K. Ko¨nigsmann (Freiburg), U. Lynen (GSI Darmstadt), G. Mairle (Mannheim), O. Nachtmann (Hei- delberg), H.J. Pirner (Heidelberg), B. Stech (Heidelberg), and Th. Walcher (Mainz) for their critical reading and helpful comments on some sections. Many students who attended our lecture in the 1991 and 1992 summer semesters helped us through their criticism to correct mistakes and improve unclearpassages.WeowespecialthankstoM.Beck,Ch.Bu¨scher,S.Fabian, Th. Haller, A. Laser, A. Mu¨cklich, W. Wander, and E. Wittmann. M.Lavelle(Barcelona)hastranslatedthemajorpartofthebookandput itinthepresentlinguisticform.Wemuchappreciatedhisclosecollaboration with us. The English translation of this book was started by H. Hahn and M. Moinester (Tel Aviv) whom we greatly thank. NumerousfiguresfromtheGermantexthavebeenadaptedfortheEnglish edition by J. Bockholt, V. Tra¨umer, and G. Vogt of the Max-Planck-Institut fu¨r Kernphysik in Heidelberg. We would like to extend our thanks to Springer-Verlag, in particular W. Beiglbo¨ck for his support and advice during the preparation of the Ger- man and, later on, the English editions of this book. Heidelberg, May 1995 Bogdan Povh Klaus Rith Christoph Scholz Frank Zetsche Table of Contents 1 Hors d’œuvre............................................. 1 1.1 Fundamental Constituents of Matter...................... 1 1.2 Fundamental Interactions................................ 2 1.3 Symmetries and Conservation Laws....................... 4 1.4 Experiments ........................................... 5 1.5 Units ................................................. 6 Part I Analysis: The Building Blocks of Matter 2 Global Properties of Nuclei............................... 11 2.1 The Atom and its Constituents........................... 11 2.2 Nuclides............................................... 13 2.3 Parametrisation of Binding Energies ...................... 18 2.4 Charge Independence of the Nuclear Force and Isospin ...... 21 Problem ................................................... 23 3 Nuclear Stability ......................................... 25 3.1 β-Decay............................................... 26 3.2 α-Decay............................................... 31 3.3 Nuclear Fission ........................................ 33 3.4 Decay of Excited Nuclear States.......................... 35 Problems .................................................. 39 4 Scattering ................................................ 41 4.1 General Observations About Scattering Processes........... 41 4.2 Cross Sections ......................................... 44 4.3 The “Golden Rule” ..................................... 48 4.4 Feynman Diagrams ..................................... 49 Problems .................................................. 52 5 Geometric Shapes of Nuclei .............................. 53 5.1 Kinematics of Electron Scattering ........................ 53 5.2 The Rutherford Cross-Section............................ 56 5.3 The Mott Cross-Section ................................. 60 X Table of Contents 5.4 Nuclear Form Factors ................................... 61 5.5 Inelastic Nuclear Excitations............................. 69 Problems .................................................. 71 6 Elastic Scattering off Nucleons............................ 73 6.1 Form Factors of the Nucleons ............................ 73 6.2 Quasi-elastic Scattering ................................. 78 6.3 Charge Radii of Pions and Kaons......................... 80 Problems .................................................. 82 7 Deep Inelastic Scattering ................................. 83 7.1 Excited States of the Nucleons ........................... 83 7.2 Structure Functions..................................... 85 7.3 The Parton Model...................................... 88 7.4 Interpretation of Structure Functions in the Parton Model ... 91 Problems .................................................. 94 8 Quarks, Gluons, and the Strong Interaction .............. 97 8.1 The Quark Structure of Nucleons......................... 97 8.2 Quarks in Hadrons ..................................... 102 8.3 The Quark–Gluon Interaction............................ 103 8.4 Scaling Violations of the Structure Functions .............. 107 Problem ................................................... 111 9 Particle Production in e+e− Collisions.................... 113 9.1 Lepton Pair Production ................................. 114 9.2 Resonances ............................................ 118 9.3 Non-resonant Hadron Production......................... 123 9.4 Gluon Emission ........................................ 125 Problems .................................................. 126 10 Phenomenology of the Weak Interaction.................. 127 10.1 Properties of Leptons ................................... 128 10.2 The Types of Weak Interactions.......................... 132 10.3 Coupling Strength of the Weak Interaction ................ 134 10.4 The Quark Families..................................... 139 10.5 The Lepton families .................................... 142 10.6 Majorana Neutrino? .................................... 144 10.7 Parity Violation........................................ 144 10.8 Deep Inelastic Neutrino Scattering........................ 147 Problems .................................................. 150 Table of Contents XI 11 Exchange Bosons of the Weak Interaction ................ 151 11.1 Real W and Z Bosons................................... 151 11.2 Electroweak Unification ................................. 156 Problem ................................................... 163 12 The Standard Model ..................................... 165 Part II Synthesis: Composite Systems 13 Quarkonia ................................................ 171 13.1 The Hydrogen Atom and Positronium Analogues ........... 171 13.2 Charmonium........................................... 174 13.3 Quark–Antiquark Potential .............................. 177 13.4 The Chromomagnetic Interaction......................... 180 13.5 Bottonium and Toponium ............................... 181 13.6 The Decay Channels of Heavy Quarkonia.................. 183 13.7 Decay Widths as a Test of QCD.......................... 185 Problems .................................................. 187 14 Mesons Made from Light Quarks ......................... 189 14.1 Mesonic Multiplets ..................................... 189 14.2 Meson Masses.......................................... 193 14.3 Decay Channels ........................................ 195 14.4 Neutral Kaon Decay .................................... 197 Problems .................................................. 199 15 The Baryons.............................................. 201 15.1 The Production and Detection of Baryons ................. 201 15.2 Baryon Multiplets ...................................... 207 15.3 Baryon Masses ......................................... 210 15.4 Magnetic Moments ..................................... 213 15.5 Semileptonic Baryon Decays ............................. 217 15.6 How Good is the Constituent Quark Concept? ............. 225 Problems .................................................. 226 16 The Nuclear Force........................................ 229 16.1 Nucleon–Nucleon Scattering ............................. 230 16.2 The Deuteron.......................................... 234 16.3 Nature of the Nuclear Force ............................. 237 Problems .................................................. 243 XII Table of Contents 17 The Structure of Nuclei .................................. 245 17.1 The Fermi Gas Model................................... 245 17.2 Hypernuclei............................................ 250 17.3 The Shell Model........................................ 253 17.4 Deformed Nuclei ....................................... 261 17.5 Spectroscopy Through Nuclear Reactions.................. 264 17.6 β-Decay of the Nucleus.................................. 271 17.7 Double β-decay ........................................ 279 Problems .................................................. 283 18 Collective Nuclear Excitations ............................ 285 18.1 Electromagnetic Transitions ............................. 286 18.2 Dipole Oscillations...................................... 289 18.3 Shape Oscillations ...................................... 297 18.4 Rotation States ........................................ 300 Problems .................................................. 309 19 Nuclear Thermodynamics ................................ 311 19.1 Thermodynamical Description of Nuclei ................... 312 19.2 Compound Nuclei and Quantum Chaos ................... 314 19.3 The Phases of Nuclear Matter............................ 317 19.4 Particle Physics and Thermodynamics in the Early Universe . 322 19.5 Stellar Evolution and Element Synthesis................... 330 Problems .................................................. 336 20 Many-Body Systems in the Strong Interaction............ 337 A Appendix................................................. 341 A.1 Accelerators ........................................... 341 A.2 Detectors.............................................. 348 A.3 Combining Angular Momenta ............................ 358 A.4 Physical Constants ..................................... 360 Solutions to the Problems .................................... 361 References.................................................... 385