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andreI sakharoV Quarks and the structure of Matter 8494_9789814407410_tp.indd 1 8/1/13 4:56 PM January10,2013 10:15 9inx6in AndreiSakharov:QuarksandtheStructure… b1456-fm TThhiiss ppaaggee iinntteennttiioonnaallllyy lleefftt bbllaannkk andreI sakharoV Quarks and the structure of Matter Harry J Lipkin Weizmann Institute of Science, Israel World Scientific NEW JERSEY • LONDON • SINGAPORE • BEIJING • SHANGHAI • HONG KONG • TAIPEI • CHENNAI 8494_9789814407410_tp.indd 2 8/1/13 4:56 PM 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 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. ANDREI SAKHAROV Quarks and the Structure of Matter Copyright © 2013 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. ISBN 978-981-4407-41-0 (pbk) Typeset by Stallion Press Email: [email protected] Printed in Singapore. Lerh Feng - Andrei Sakharov.pmd 1 1/8/2013, 2:31 PM January10,2013 12:1 9inx6in AndreiSakharov:QuarksandtheStructure… b1456-fm Contents Preface vii Chapter1. QuarksandSmuggledPostcards fromAndreiSakharov 1 Chapter2. AndreiSakharovandtheWeizmannInstitute 19 Chapter3. TheWeizmannInstituteandtheScientific Historyof Sakharov’sWork 29 Chapter4. HowScientistsStudyNature—Pure andAppliedResearch 47 Chapter5. TheBuildingBlocksof Matter—What isaQuark? 85 Chapter6. TheForcesof Nature 121 Chapter7. TheWeakForceandtheDiscovery of theWParticle 137 Index 147 v January10,2013 10:15 9inx6in AndreiSakharov:QuarksandtheStructure… b1456-fm TThhiiss ppaaggee iinntteennttiioonnaallllyy lleefftt bbllaannkk January10,2013 10:15 9inx6in AndreiSakharov:QuarksandtheStructure… b1456-fm Preface AndreiSakharov—adistinguishedRussianphysicist Sakharov was the “father of the Russian hydrogen bomb’ and also madegreatcontributionstoourunderstandinganduseof physics. He pioneered the search for a way to tame the awesome fusion energythatexplodedthehydrogenbomb.Hedevelopedmethodsthat couldenablefusionenergytobeusedforpeacefulpurposes.Healso investigatedthepropertiesofmatter.Weknewthenthattherearetwo kindsofmattercalledmatterandantimatter.Bothkindswerecreated in laboratory experiments but the universe we knew contained only matterandnoantimatter.Thisincludedallthestarsandgalaxiesseen byastronomers.Theiropticalinstrumentscoulddistinguishbetween light coming from matter and light from antimatter. They saw only lightfrommatter.Themysteryoftheabsenceofantimatteroccupied physicistsformanyyears.Sakharovwasthefirsttosolvethismystery. Both matter and antimatter were created equally in the “big bang” theory of the origin of the universe. Sakharov showed how all the antimatter could decay leaving only matter. This matter–antimatter problemisstillnotsolvedbutallsearchesstartwiththeseminalwork ofAndreiSakharov. Saharov also investigated the structure of matter which was knowntomadeofatomscontainingprotons,electronsandnuclei.In 1964thePhysicistsGell-MannandZweigproposedthattheneutrons andprotonswerereallymadeofsmallerconstituentscalled“quarks”. Thephysicscommunityrejectedthequarkpictureasnonsense.But SakharovandhiscolleagueZeldovichinvestigatedthisquarkmodel and found very interesting results. At the same time this quark vii January10,2013 10:15 9inx6in AndreiSakharov:QuarksandtheStructure… b1456-fm (cid:1) AndreiSakharov:QuarksandtheStructureofMatter (cid:1) modelwasindependentlyinvestigatedbymygroupattheWeizmann InstituteinRehovot,Israel.Butwedidnotknowof theirworkuntil muchlater. Sakharov was treated by his government as a great hero until he began to criticize the Russian Government. He wrote critical articleswhichwerecirculatedabroad.Thegovernmentthenarrested Sakharovandsentencedhimtoisolationinthecityof Gorkywhich was closed to foreigners. Despite all these restrictions he continued to do scientific work. He was not allowed to publish his work or sendittophysicistsabroad.In1980hiswifeandfriendsmanagedto smugglesomeofhisworkabroadandtriedtogetitpublishedinthe UnitedStates.TheAmericanshesitatedbecausetheywereafraidthat theRussianswouldclaimthatSakharov’sworkwasbeingpublished only for political reasons. They wanted to be sure that it was a good scientificpaperthatwouldbeacceptedonpurelyscientificgrounds. My colleague Tom Ferbel was asked to review Sakharov’s paper. Since it was on the quark model of matter and I was a recognized expertatthetime,Tomaskedmetoreviewthepaper.Iwasamazedto findthatitwasidenticaltoworkIwasdoinginRehovot.Thisledto publicitywithinternationalimplications.TheRussianshadclaimed that Sakharov was a great man, but he was now old and senile and isolated for his own good. My analysis of his work showed that the Russian excuse was simply wrong. Sakharov was not senile. On the contrary he was engaged in great physics research. The Washington Postlearnedof myanalysisandpublishedanarticleaboutSakharov and my work with a title“A voice out of the darkness”. This led to a flood of articles in the media and led me to give a series of popular scientific lectures and magazine and newspaper articles for a wide variety of general audiences, including Rotary Clubs, high school students, laymen interested in science, and professors in the social sciences and humanities. These lectures were first motivated by the attemptstohelpAndreiSakharov. Myfurthercontactswiththescientificworkof Sakharovturned into a remarkable adventure in which I received more manuscripts viii January10,2013 10:15 9inx6in AndreiSakharov:QuarksandtheStructure… b1456-fm (cid:1) Preface (cid:1) and postcards from him in his exile in Gorky, smuggled out of the Soviet Union. The story of this adventure and of Sakharov’s work and achievements fit beautifully into the description of what scientific research is all about and how it is done. The quarks which were then rejected as nonsense are now recognized as the basic tiny building blocks which are bound together to make the matter we know.LecturesoriginallygivenforpublicityofSakharov’splightgrew into lectures and articles which fascinated many general audiences, professors and professionals in other fields, and newspaper and magazine editors and readers. They all responded enthusiastically tothiscombinationofthehumanintereststoryandachievementsof Sakharovwithanunderstandabledescriptionofmodernphysicsand thepresentstateofourknowledgeofthenatureofmatterandenergy. Iexplainedhowthequarkbuildingblocksofmatterwerediscovered andunderstood.Ialsopresentedapictureofhowhowscientistswork anddevelopnewknowledge,anddiscussedthepurposeof itall. Professor Moshe Barasch of the Hebrew University and Mosad BialiksuggestedthatIputthematerialtogetherinabook.Thisbook grewoutof theselectures. Fromearth,air,fireandwatertoquarks Throughoutthecenturies,scientistshavepuzzledoverthequestions, what is matter made of, and what are the forces of nature. The ancients believed that everything was composed of four elements, earth, air, fire and water. Now we know that water is a compound made of hydrogen and oxygen and that fire is a chemical reaction thatproducesenergywhichcanbebothusefultomankindandcause terrible destruction. Earth and air are mixtures of many different chemicalelementsandcompounds. During the twentieth century scientists have made very great progressinunderstandingthenatureofmatterandenergy.Theyhave foundnewsourcesofenergy,whichlikefirearealsocapableofterrible destruction and of being harnessed to do useful work for mankind. ix