Graduate Texts in Physics For further volumes: www.springer.com/series/8431 Graduate Texts in Physics Graduate Texts in Physics publishes core learning/teaching material for graduate- and ad- vanced-level undergraduate courses on topics of current and emerging fields within physics, both pure and applied. These textbooks serve students at the MS- or PhD-level and their instructors as comprehensive sources of principles, definitions, derivations, experiments and applications (as relevant) for their mastery and teaching, respectively. International in scope and relevance, the textbooks correspond to course syllabi sufficiently to serve as required reading. Their didactic style, comprehensiveness and coverage of fundamental material also make them suitable as introductions or references for scientists entering, or requiring timely knowledge of, a research field. Series Editors Professor Richard Needs Cavendish Laboratory JJ Thomson Avenue Cambridge CB3 0HE, UK [email protected] Professor William T. Rhodes Department of Computer and Electrical Engineering and Computer Science Imaging Science and Technology Center Florida Atlantic University 777 Glades Road SE, Room 456 Boca Raton, FL 33431, USA [email protected] Professor Susan Scott Department of Quantum Science Australian National University Science Road Acton 0200, Australia [email protected] Professor H. Eugene Stanley Center for Polymer Studies Department of Physics Boston University 590 Commonwealth Avenue, Room 204B Boston, MA 02215, USA [email protected] Professor Martin Stutzmann Walter Schottky Institut TU München 85748 Garching, Germany [email protected] Anwar Kamal Particle Physics Anwar Kamal (deceased) Murphy, TX, USA ISSN 1868-4513 ISSN 1868-4521 (electronic) Graduate Texts in Physics ISBN 978-3-642-38660-2 ISBN 978-3-642-38661-9 (eBook) DOI 10.1007/978-3-642-38661-9 Springer Heidelberg New York Dordrecht London Library of Congress Control Number: 2014939316 ©Springer-VerlagBerlinHeidelberg2014 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of pub- lication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Dedicated to my parents Preface This is an introductory textbook of particle physics for upper undergraduate stu- dents. The book is based on lectures given at British, American and Indian Univer- sities over several years. The idea of writing a textbook on this subject was mooted some forty years ago. But it was never easy to write on a subject like particle physics which started expanding explosively in sixties and seventies. All this happened due to the development of high energy accelerators and sophisticated detecting systems on the experimental side, paralleled by new concepts on the theoretical side. And it became very difficult to keep pace with the rapidly changing scenario. Now, when the dust is settled down and the underlined physics is understood in a big way, al- though quite a bit is still obscure, there appears a justification in expounding the basic ideas of particle physics in the form of a textbook. It is attempted to survey the major developments in particle physics during the past 100 years. In Ruther- ford’s time and early 1950s, only a few Elementary particles were known and the existence of neutrino was taken for granted. At that time, the entire knowledge of elementary particles and cosmic rays was so scanty that it could be accommodated in a single chapter. But, a few decades ago, particle physics branched off from nu- clear physics and became virtually an independent discipline. No text book would be balanced until equal weightage is given to these two disciplines. There is also a complementary textbook on nuclear physics available by the same author. The development of the subject is so fascinating that we were inclined to present the historical facts in the chronological order. The prerequisites for the use of this book are the elements of quantum mechanics comprising Schrodinger’s equation and applications, Born’s approximation, the golden rule, differential equations and Vector Calculus. Basic concepts are explained with line diagrams wherever required. An attempt is made to strike a balance between theory and experiment. Theoretical predictions are compared with latest observations to show agreement or discrepancies with the theory. The subject matter is developed in each chapter with necessary mathematical details. Feynman diagrams are used extensively to explain the fundamental interac- tions. vii viii Preface The subject matter in various chapters is so much intimately connected that the logical sequential presentation of various topics becomes a vexing problem. For ex- ample, from the point of view of introducing quarks, the logical sequence would be strong, electromagnetic, weak and electroweak interactions, but from the point of view of introducing Feynman’s diagrams, the desirable sequence would be electro- magnetic, weak, electroweak and strong interactions, which is why one finds vari- ance in sequences for both Nuclear and Particle physics in various textbooks. The only remedy is to make cross references to the chapters which were studied before and to those in which the relevant material is anticipated. At the end of each chapter, a set of questions is given. A large number of worked examples are given. A comparable number of unworked problems with answers is delivered in the book to test the understanding of the student. The examples and problems are not necessarily of plug-in type but are given to explain the underlying physics. Various useful appendices are provided at the end of the book. Murphy, TX Anwar Kamal Note:ThesetwovolumesarethelastbooksbymyfatherDr.AhmadKamal,the work he had conceived as his dream project and indeed his scientific masterpiece. Unfortunately, he passed away before he could see his manuscript in print. While we have tried our best to bring the publishing process to as satisfactory conclusion as possible, we regret any errors you may discover, in particular, that some of the references could not be as completely specifically cited as would otherwise be the case. We trust that these errors however do not compromise the quality or standard of the content of the text. Suraiya Kamal Daughter of Dr. Ahmad Kamal Acknowledgements IamgratefultoGodforhelpingustocompletethedreamprojectofDr.Ahmad Kamal after his demise, which seemed very difficult and even impossible at times. IwouldliketothankSpringer-Verlag,inparticularDr.ClausAsheron,Mr.Do- natas Akmanavicius,ˇ Ms. Adelheid Duhm and Ms. Elke Sauer for their constant encouragement, patience, cooperation, and for bringing the book to its current form. This project would not be complete without the constant support and encourage- ment of Mrs. Maryam Kamal, wife of Dr. Ahmad Kamal. Her determination kept us all moving to get these books done. My sincere thanks is due to the family, friends and well-wishers of the author who helped and prayed for the completion of these books. Suraiya Kamal Daughter of Dr. Ahmad Kamal ix Contents 1NuclearRadiationDetectors...................... 1 1.1 Classification of Detectors . 1 1.2 Ionization Chambers . 3 1.2.1 Ionization Chambers . 3 1.2.2 Pulse Chambers . 3 1.2.3 Gas-Filled Pulse Counter ................. 4 1.2.4 Variation of Pulse Sizes . 5 1.3 Proportional Counter ........................ 7 1.3.1 Construction . 7 1.4 Geiger Muller Counter ....................... 7 1.4.1 Construction and Characteristics . 7 1.4.2 Pulse Formation and Decay ............... 9 1.4.3 Quenching the Discharge ................. 10 1.4.4 Scaling Circuits . 12 1.5 Resolving Time . 12 1.5.1 Determination of Resolving Time: Double Source Method .................. 13 1.6 Resolving Time of a Coincidence Circuit ............. 14 1.6.1 Determination of the Resolving Time of the Coincidence Circuit ................ 14 1.7 Semi-conductor Particle Detectors ...............