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The purpose of this book is to introduce 4th-year or senior undergraduate students to what is known as the Standard Model of Particle Physics, the model that presently encompasses all of our empirical knowledge about the subject. Particle physics was in a near-continual state of flux for several decades, finally settling down around the mid 1990s when the mass of the Z boson had been accurately measured, the number of light quarks and leptons had been established, and the top quark had been discovered. The Standard Model has since then faced pretty much every experimental challenge to its authority with flying colors, and today it stands as the established fundamental theory of the non-gravitational interactions, describing all known forms of subatomic matter that we have observed. The goal of this book is to familiarize students with the Standard Model and in so doing, with particle physics in general. It grew out of a one-term course I have taught at the University of Waterloo nearly every year over the past two decades. It was an interesting course to teach because the subject matter would change as particle physics continued to develop, with new results coming out from LEP, Fermilab, Super-K, SNO and more on the experimental side, and from supersymmetry, string theory, and lattice gauge theory on the theoretical side. Students taking the course typically had taken at least one course in quantum mechanics (in which they would have seen the solution to the hydrogen atom from Schroedinger’s equation), one in mathematical physics (covering vector calculus, Fourier transforms, and complex functions), and had a solid background in special relativity (having encountered the basic phenomena of length contraction and time dilation). This book assumes that students have a good working knowledge of special relativity, quantum mechanics, and electromagnetism. From this basis students who work through the material will develop a solid command of the subject and a good working knowledge of the basics of particle physics, in terms of mathematical foundations, experimental methods, and basic processes. Each chapter has a number of questions, and there is a solutions manual available that has complete answers to all of the questions. I have taken the approach of describing the Standard Model in terms of its Electromagnetic, Strong, and Weak components, so that students can understand the subject from the perspective of the reigning paradigm. Throughout I have endeavored to show why this paradigm does indeed reign – in other words, how and why the different parts of the Standard Model came to be xiii xiv what they are today, particularly pointing out and describing the experiments that were essential in arriving at these conclusions. I have also made efforts to show where the Model is in need of improvement and what possible physics might lie beyond what it describes. This is particularly addressed in the last chapter, but also appears throughout the book in a number of places. Our understanding of particle physics is by no means a finished project, and I hope that students will catch the excitement of the ongoing nature of research in this subject. Particle physics is both mathematically and conceptually challenging, and many have thought that it can only be taught in a very superficial way at the undergraduate level, if it is taught at all. In my 20 years of teaching this subject I have found that students can indeed rise to the challenge, if both the formalism and background are carefully explained to them in a manner that allows them to connect with the physics they have already learned. I have taken that approach in this book, beginning (after a review of relativity) with some basic concepts in group theory and classical mechanics that lead into the subjects of symmetries, conservation laws, and particle classification. Three chapters following that are devoted to the experimental tools and methods, and analysis of particle physics. The next three chapters introduce students to Feynman diagrams, wave equations, and gauge invariance, building up to the theory of Quantum Electrodynamics. The remainder of the book then deals with the three pillars of the Standard Model: QED in Chapters 13 and 14, the strong interactions and QCD in Chapters 15 – 18, and Electroweak interactions in Chapters 19 – 24, with the final chapter devoted to what might lie beyond the Standard Model. I have also taken an historical approach to the development of the subject wherever possible, showing how it emerged from the physics that most students have learned about in other courses. The book is designed to be used in a single course over one term, essentially twelve weeks of lectures in a three-hour lecture week. Though I would typically cover two chapters per week, there is a bit too much in the book for one term, and so a few topics inevitably get scant attention. I suggest that students read the first chapter on their own, and that instructors need cover only the formalism in chapter 2 that may be unfamiliar to students. Instructors may also wish to omit the material on the Higgs mechanism in Chapter 23, and perhaps the material on QCD in Chapter 18 if time does not permit. Theoretical Particle Physics rests on the foundation of Quantum Field Theory (QFT), that subject combining both special relativity and quantum mechanics into a unified whole. I have found that students can learn and make use of the basic results of QFT – Feynman diagrams, scattering amplitudes, antiparticles, decay processes – without having to go through a full discussion of path integrals, Wick’s theorem, Interaction pictures, and the like. I have avoided the use of the language of quantum fields, preferring to use the term wavefunction so that students can make better contact with what they are familiar with. Throughout the book I acknowledge the quantum field theoretic foundations on which the subject stands where appropriate. My goal is that xv students see both the forest and the trees, and not get too bogged down in formalism. That said, the subject is one requiring serious mathematical and intellectual effort. I have attempted to cater to the more mathematically inclined students by putting into appendices mathematically challenging material that enriches but is not essential to the understanding of the material in a given chapter. Any appendix can be avoided in a first reading of the book, and most students will probably wish to do this. However, calculational derivations are made explicit wherever possible, and students willing to work through the appendices will be rewarded with an enriched understanding of the material and a set of formidable technical skills. It is my hope that undergraduate students reading this book or taking a course that makes use of this book will be inspired by the subject of particle physics. I also hope that beginning graduate students may be able to make use of the book as preparation for more advanced courses they might take or as a resource for basic calculations and background material. I have tended to err on the side of completeness in my discussion to ensure that students are able to make use of the book in as broad a range of applications as possible. This book was written while I was at the University of Waterloo in Ontario, Canada, and completed while I was on sabbatical at the Kavli Institute for Theoretical Physics at the University of California, Santa Barbara, California U.S.A., for whose hospitality I am most grateful. I am also grateful to Don Marolf and Martin Einhorn for their efforts in ensuring that I could be hosted there.

Item Type: Book
Subjects: L Education > L Education (General)
Q Science > Q Science (General)
Depositing User: user user2 2
Date Deposited: 09 May 2022 00:10
Last Modified: 09 May 2022 00:10

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