Elementary Particles: Building Blocks Of Matter

ELEMENTARY PARTICLES Building Blocks of Matter This page intentionally left blank ELEMENTARY PARTICLES Building Blocks of Matter Harald Fritzsch University of Munich, Germany Translated by Karin Heusch We World Scientific NEW JERSEY · LONDON · SINGAPORE · BEIJING · SHANGHAI · HONG KONG · TAIPEI · CHENNAI Published by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore 596224 USA office: 27 Warren Street, Suite 401-402, Hackensack, NJ 07601 UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE Library of Congress Cataloging-in-Publication Data Fritzsch, Harald, 1943– [Elementarteilchen. English] Elementary particles : building blocks of matter / Harald Fritzsch. p. cm. ISBN 981-256-141-2 (alk. paper) 1. Particles (Nuclear physics)--Popular works. 2. Quantum chromodynamics--Popular works. 3. Quantum electrodynamics--Popular works. I. Title. QC793.26 .F7513 2005 539.7'2--dc22 2005044181 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. Copyright © 2005 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. This book, or parts thereof, may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the Publisher. For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from the publisher. Printed in Singapore. Contents 1. Introduction 1 2. Electrons and Atomic Nuclei 11 3. Quantum Properties of Atoms and Particles 21 4. The Knives of Democritus 33 5. Quarks Inside Atomic Nuclei 45 6. Quantum Electrodynamics 53 7. Quantum Chromodynamics 67 8. Mesons, Baryons and Quarks 79 9. Electroweak Interactions 87 10. Grand Unification 95 11. Conclusion 103 Index 109 v This page intentionally left blank Chapter 1 Introduction Philosophers in Antiquity were already tackling the question: what does matter surrounding us ultimately consists of? Will we hit a boundary when we take a piece of material, say, a piece of wood or a diamond, and break it down into smaller pieces? If so, what defines that boundary? Are there minuscule objects that can no longer be split up? Or is that boundary simply that a further division, for whatever reason, does not make sense any longer? Let me give an analogy, starting from the question: what are the original elements of, say, the German library in the city of Leipzig or, for that matter, of any large library? To find out, we step into that library and find thousands of books. We open a book and discover the building blocks of that book – often more than a hundred thousand words. We recall that there are dictionaries that contain information about all of those words – tens of thousands of them. And each of these words is made up of letters. Our alphabet contains twenty-six different letters. All of the words in the books are made up of these twenty-six letters. These days, books are often written on the computer. The word processor in the computer writes these letters in terms of sequences of the symbols zero and one – they are digitally produced just like the Morse code which allows the letters to be shown as a series of 1 2 Elementary Partic