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Nuclear and Particle Physics

Claude Amsler

Albert Einstein Center for Fundamental Physics, Laboratory for High Physics, University of Bern, Switzerland

Emeritus Professor, University of Zurich, Switzerland

IOP Publishing, Bristol, UK ª IOP Publishing Ltd 2015

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the publisher, or as expressly permitted by law or under terms agreed with the appropriate rights organization. Multiple copying is permitted in accordance with the terms of licences issued by the Copyright Licensing Agency, the Copyright Clearance Centre and other reproduction rights organisations.

Permission to make use of IOP Publishing content other than as set out above may be sought at [email protected]. This textbook was originally published in 2007 by vdf Hochschulverlag AG at ETH Zurich. The current version is a translation into English, which has been substantially expanded.

Claude Amsler has asserted his right to be identified as author of this in accordance with sections 77 and 78 of the Copyright, Designs and Patents Act 1988.

ISBN 978-0-7503-1140-3 (ebook) ISBN 978-0-7503-1141-0 (print) ISBN 978-0-7503-1142-7 (mobi)

DOI 10.1088/978-0-7503-1140-3

Version: 20150501

IOP Expanding Physics ISSN 2053-2563 (online) ISSN 2054-7315 (print)

British Library Cataloguing-in-Publication Data: A catalogue record for this book is available from the British Library.

Published by IOP Publishing, wholly owned by The Institute of Physics, London

IOP Publishing, Temple Circus, Temple Way, Bristol, BS1 6HG, UK

US Office: IOP Publishing, Inc., 190 North Independence Mall West, Suite 601, Philadelphia, PA 19106, USA Contents

Preface xii Author biography xiii

1 The discovery of the atomic nucleus 1-1 1.1 Rutherford scattering 1-3 1.1.1 Remarks on units 1-6 1.1.2 Interpretation of the differential cross section 1-7 1.1.3 Remarks on Rutherford scattering 1-9 References 1-11

2 The nuclear radius 2-1 2.1 Mott scattering 2-1 2.2 Form factor 2-3 2.3 Muonic atoms 2-9 2.4 form factor 2-10 References 2-15

3 Nuclear 3-1 3.1 The Fermi gas model 3-6 3.2 The liquid drop model 3-10 References 3-13

4 Radioactive decay 4-1 4.1 Decay law 4-1 4.2 Partial and total widths 4-5 4.3 Poisson statistics 4-8 References 4-9

5 Nuclear stability 5-1 5.1 γ-decay 5-2 5.2 β-decay 5-5 5.3 α-decay 5-8 5.4 Fission 5-15

v Nuclear and Particle Physics

5.4.1 Spontaneous fission 5-15 5.4.2 Induced fission 5-16 5.5 Radiation dosimetry 5-20 References 5-22

6 The 6-1 6.1 The electric quadrupole moment 6-7 References 6-12

7 Elementary particles 7-1 7.1 Introduction 7-1 7.2 and 7-4 7.3 Interactions 7-6 7.3.1 Conservation laws 7-9 7.3.2 Exchange 7-11 7.3.3 Charged and neutral currents 7-14 7.3.4 Cross section and mean lifetime 7-15 7.4 Beyond the 7-17 References 7-20

8 Relativistic kinematics 8-1 8.1 π0 → 2γ 8-3 8.2 8-9 8.3 π → μν 8-10 8.4 Mandelstam variables s and t 8-13 8.5 Proper 8-14 8.6 Rapidity 8-15 References 8-19

9 Accelerators and detectors 9-1 9.1 Accelerators 9-1 9.2 Charged particle interaction with matter 9-9 9.3 Multiple scattering 9-14 9.4 Energy loss of 9-17 9.5 Interaction of with matter 9-18 9.6 Wire chambers 9-23

vi Nuclear and Particle Physics

9.7 Scintillation counters 9-26 9.8 Bubble chambers 9-27 9.9 Segmented silicon detectors 9-29 9.10 Čerenkov counters 9-31 9.11 Transition radiation detectors 9-33 9.12 Electromagnetic calorimeters 9-36 9.13 Hadronic calorimeters 9-38 References 9-39

10 The model 10-1 10.1 Strangeness 10-1 10.2 The spectrum 10-3 10.2.1 Mesons 10-3 10.2.2 Baryons 10-7 10.2.3 Isospin 10-10 10.2.4 OZI rule 10-13 10.3 Charm and bottom 10-13 10.3.1 Charmonium 10-17 10.3.2 Bottomonium 10-21 10.3.3 10-23 10.4 Colour 10-25 10.5 The top quark 10-29 References 10-31

11 Conservation laws 11-1 11.1 conservation 11-2 11.2 11-3 11.3 Parity 11-4 11.4 Internal parity 11-8 11.5 Gauge invariance 11-12 11.6 The helicity of the 11-14 11.7 11-21 11.8 Time reversal invariance 11-25 11.8.1 Magnetic and electric moments 11-26 11.9 CPT invariance 11-30 References 11-32

vii Nuclear and Particle Physics

12 Hadronic interactions 12-1 12.1 Cross section 12-1 12.2 Two-body final state 12-2 12.2.1 Detailed balance 12-4 12.3 Three-body final state 12-6 12.3.1 The of the charged 12-9 12.3.2 The spin of the ω 12-10 12.3.3 Invariant mass distribution 12-12 12.4 Charge independence and isospin invariance 12-15 12.4.1 Nucleon–nucleon scattering 12-17 12.4.2 –nucleon scattering 12-19 12.5 G parity 12-22 References 12-25

13 Weak interactions 13-1 13.1 The discovery of the 13-3 13.1.1 Neutron lifetime 13-4 13.2 β-decay 13-5 13.2.1 Allowed and forbidden transitions 13-6 13.2.2 ft-value 13-12

13.2.3 Coupling constants GF and gA/gV 13-13 13.2.4 Sargent rule 13-14 13.3 Parity violation 13-16 13.3.1 Parity violation in nuclear β-decay 13-16 13.3.2 Parity violation in production and decay 13-18 13.3.3 The anomalous magnetic moment of the muon 13-21 References 13-24

14 14-1 14.1 The discovery of the 14-1 14.2 Mass measurements 14-4

14.2.1 νe mass 14-4 14.2.2 Solenoid retarding spectrometers 14-6

14.2.3 νμ and ντ masses 14-9 14.3 Solar neutrinos 14-11 14.4 The helicity of the neutrino 14-15 14.5 Dirac and Majorana neutrinos 14-17

viii Nuclear and Particle Physics

14.6 Neutrino oscillations 14-19 14.6.1 The oscillation mechanism 14-22 14.6.2 Oscillations between three neutrino flavours 14-24 2 14-26 14.6.3 Δm23 oscillations 2 14-29 14.6.4 Δm12 oscillations

14.6.5 Measurement of θ13 14-30 14.6.6 Matter effects on neutrino oscillations 14-33 14.6.7 The MSW effect in the Sun 14-36 References 14-38

15 The 15-1 15.1 Standard representation 15-5 15.2 The discovery of the positron and of the antiproton 15-9 15.3 and handedness 15-11 15.4 Parity 15-13 15.5 Charge conjugation 15-14 15.6 Current 15-14 15.6.1 Current–current interaction 15-15 References 15-18

16 The 16-1 16.1 V – A interaction 16-1 16.2 Weak isospin 16-7 16.2.1 Weak neutral currents 16-10 16.3 GIM mechanism 16-14 16.4 Gauge invariance in QED 16-19 16.5 Spontaneous breaking 16-22 16.6 Gauge invariance in the electroweak interaction 16-27 16.7 The Glashow–Weinberg–Salam model 16-30 References 16-41

17 Applications of the standard model 17-1 17.1 Parity violation in scattering 17-1 17.2 The discovery of the W± and Z0 bosons 17-6 17.2.1 W width 17-12 17.2.2 Z0 width 17-15

ix Nuclear and Particle Physics

17.3 The discovery of the 17-18 17.3.1 Width of the Higgs boson 17-23 17.4 Neutrino scattering 17-25 17.4.1 Charged currents 17-25 17.4.2 Neutrino–quark scattering 17-28 17.4.3 Neutral currents 17-31 17.4.4 Purely leptonic reactions 17-33 References 17-37

18 Deep inelastic electron– scattering 18-1 References 18-12

19 The K 0 − K 0 system 19-1

19.1 The K1 and K2 mesons 19-1

19.1.1 Lifetimes of the K1 and K2 mesons 19-5 19.1.2 KK0 − 0 oscillations 19-8 19.1.3 Regeneration 19-10 19.2 CP violation 19-12 19.2.1 Indirect CP violation 19-14 19.2.2 Direct CP violation 19-19

19.3 Semileptonic KL decays 19-22 19.3.1 T violation 19-24 References 19-26

20 The B 0 − B 0 system 20-1 20.1 The CKM matrix 20-1 20.2 B0 − B 0 oscillation 20-3 0 0 20-7 20.3 Bss− B oscillation 20.4 CP violation in the B0 − B 0 system 20-9 References 20-15

Appendices

A SU(3) wave functions of the light ground state mesons A-1

B Mass formula B-1

x Nuclear and Particle Physics

C SU(3) wave functions of light ground state baryons C-1

D The CKM matrix and CP violation D-1

E Infinitesimal gauge field transformation E-1

F Glossary F-1

xi Preface

This textbook originated from lectures given at the Physics Institute of the University of Zurich in Switzerland between 1997 and 2012. It is intended as an introduction to nuclear and particle physics for undergraduate students at the bachelor’sandmaster’s levels. Students who intend to pursue a career in experi- mental particle physics will also find valuable information in some of the more advanced sections. This introduction into the world of nuclei and particles is presented from a his- torical viewpoint and is phenomenologically oriented. Many of the concepts and phenomena are derived with inductive rather than deductive thinking, following the paths that often led to their final formulation. A balanced blend of experiments and theory is presented. An introduction to the basic concepts of nuclear physics is given before moving on to topics in particle physics which are developed in more detail. Many formulas are derived explicitly from first principles. The reader is expected to master the basic concepts of . This textbook was originally published in 2007 in German by vdf Hochschul- verlag AG at ETH Zurich. The current version is a translation into English which has been substantially expanded to include very recent developments in neutrino, heavy quark and high energy physics. The author wishes to acknowledge the contributions from his younger physics colleagues, who carefully read parts of the manuscript: Lucian Ancu, Vincenzo Chiochia, Konrad Nesteruk, Paola Scampoli, Basil Schneider, Sarah Seif El Nasr and Mauro Verzetti.

xii Author biography

Claude Amsler

Claude Amsler studied experimental physics at the ETH in Zurich, Switzerland. He worked as a research associate at Queen Mary College in London, TRIUMF in Vancouver, the University of New Mexico and Brookhaven National Laboratory. After a CERN fellowship and a brief stay at the University of Munich he joined the Physics Institute of the University of Zurich, where he became full professor of physics in 1999. He has supervised 40 doctoral and master’s theses. He is now professor emeritus and a member of the senior staff at the Albert Einstein Center for Fundamental Physics, University of Bern. His main fields of interest are physics and meson . He is a member of the CMS Collaboration and of the Particle Data . He is currently involved in antihydrogen experiments at CERN. More can be found on his home page http://cern.ch/amsler/.

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