Professor Jeffrey D. Richman

Broida Hall 5111, 893-8408

richman@charm.physics.ucsb.edu

http://hep.ucsb.edu/people/richman/richman.html

Graduate Teaching Assistant: Finn Rebassoo

What is particle physics?

Particle physics addresses fundamental and challenging questions. What are the fundamental constituents of matter? How do they interact? What are the laws of physics that governed the behavior of matter in the early evolution of the universe?

The smallest objects observed so far—quarks, leptons, and gauge bosons—behave in a manner that we can now describe in great detail. Yet, in spite of tremendous progress in this field, many deep mysteries remain. What is the origin of mass? What is the nature of the dark matter inferred from astrophysical observations? Why do neutrinos have very tiny masses? Why is there a three-fold replication of a basic set of particles (the generation puzzle)? Are quarks truly elementary particles? Why are some conservation laws violated by a narrow class of processes? Why is there much more matter than antimatter in the universe? Is there, as theorists predict, an undiscovered ``supersymmetric’’ partner for every known type of particle? Are there additional undiscovered dimensions of space?

To make progress in the study of elementary particles, one needs sophisticated experimental and theoretical tools. We use accelerators of monumental size to produce particle collisions at energies that are equal to those 10^-12s after the big bang. We routinely collide matter with antimatter, destroying the initial particles and creating new ones. The detectors that we use to study these collisions are nearly as impressive. Here at UCSB, the high-energy physics group is very active in constructing such detectors and in analyzing the results of experiments that we perform at various accelerator laboratories.

The theoretical tools required to analyze elementary particle phenomena are also extremely interesting and challenging. Nearly all processes involve phenomena that must be described with relativistic quantum mechanics. Theories must also cope with the fact that, in high-energy collisions, particles are usually created or destroyed. In other words, we don’t simply smash two watches together and observe the little pieces come flying out---entirely new pieces are created! We have come to understand that the "new" particles observed in such experiments are every bit as fundamental and important to piecing together the puzzle of matter as the particles that make up atoms. The theoretical framework for describing these processes is called quantum field theory.

In Physics 125 we will make a start towards understanding the nature of elementary particles and their interactions. We can go quite far without using the full apparatus ofquantum field theory. We will, however, need to use special relativity and quantum mechanics routinely.

Finally, let me repeat a sentiment of a physicist I know. She said that doing particle physics is like climbing a mountain: the journey up can be a struggle, but the view from the top is great!

How to succeed in this course

You will face four main challenges in this course:

1. Unlike upper division courses in some other subjects like electromagnetism or classical mechanics, you probably have not seen this material before in a simpler form. There is a large amount of ideas, knowledge and terminology that you must learn in a very short time.

2. The course will make substantial use of quantum mechanics.

3. The course will make substantial use of special relativity.

4. The pace will be fast. If you do not keep up with the reading, HW, and absorbing the lectures, you will get lost very quickly.

If you have encountered quantum mechanics and special relativity before, this course is probably not a good use of your time right now. If you have had these subjects before, Physics 125 will help you understand them better by applying them to interesting situations.

Here is some advice on how to deal with this challenging subject.

Keep up with the reading and do the homework on time. Take careful notes when you read the textbook and bring lots of questions to class. Come to office hours to get mysterious concepts clarified!
Remember information: constants, particle names and quantum numbers, masses, lifetimes, as much as you can. You may be used to solving idealized problems that are simply meant to give you insight into applying a particular physical law. Here things are different: you need to know and understand the properties of real physical systems. In order to understand why certain observations are crucial, you must be able to put the information into context. Without the background information in your head, you will have a hard time understanding this context. Creating your own mental database also helps you to develop physical intuition in a subject that is very unfamiliar.
Remember the main results of homework problems: you will often need to use them later. Many of the problems will address important issues; they are not simply cooked-up examples.
My lectures will often cover material not mentioned in the text, but I will also expect you to read and know all of the assigned sections in the book, whether or not they are covered in lecture.

Grades, homework, tests, and all that stuff

· Homework will be assigned on Wednesday and will be due on class on the following Wednesday.

· Graduate Teaching Assistant: Finn Rebassoo

· Lectures: M, W, F 12:00—12:50 in Girvetz 2123

· Professor Richman’s office hours: tentatively, Thurs 3:00-5:00 or by appointment

· Grading policy:

1. Homework: 30%

2. Midterm: 20%

3. Final exam: 50%

· Textbook: Introduction to Elementary Particles, by David Griffiths

· Final Exam Date: see schedule below.

Approximate Schedule for Physics 125 in Spring 2007

Class	Date	Topics	Chapters and Reading
1	Mon, Apr 2	Energy and length scales	Introduction, C1 (History)
2	Weds, Apr 4	Particles and interactions	finish C1, start C2
3	Fri, Apr 6	Particles and interactions	C2
4	Mon, Apr 9	Particles and interactions	C2
5	Weds, Apr 11	Relativistic kinematics	C3
6	Fri, Apr 13	Relativistic kinematics	C3
7	Mon, Apr 16	Detectors and accelerators	Handouts
8	Weds, Apr 18	Detectors and accelerators	Handouts
9	Fri, Apr 20	Symmetries	C4
10	Mon, Apr 23	Symmetries	C4
11	Weds, Apr 25	Symmetries	C4
12	Fri, Apr 27	Feynman rules	C6
13	Mon, Apr 30	Feynman rules	C6
14	Weds, May 2	Feynman rules	C6
15	Fri, May 4	Feynman rules	Handouts
16	Mon, May 7	Neutrinos and neutrino oscillations	Handouts
17	Weds, May 9	Neutrinos and neutrino oscillations	Handouts
18	Fri, May 11	MIDTERM	C1, C3, C4, C6 (Lecs 1-14)
19	Mon, May 14	Quantum electrodynamics	C7
20	Weds, May 16	Quantum electrodynamics	C7
21	Fri, May 18	Quantum electrodynamics	C7
22	Mon, May 21	Quantum electrodynamics	C7
23	Weds, May 23	Quantum electrodynamics	C7
24	Fri, May 25	Electrodynamics of quarks & hadrons	C8.1, 8.2
-	Mon, May 28	Memorial Day Holiday
25	Weds, May 30	Weak interactions	C10
26	Fri, June 1	Weak interactions	C10
27	Mon, June 4	Weak interactions	C10
28	Weds, June 6	Weak interactions	C10
29	Fri, June 8	Weak interactions	C10
FINAL	Tues, Jun 12	FINAL EXAM noon—3:00 PM	Covers textbook, HW, lectures

The tables on the following pages are available at

http://pdg.lbl.gov/2006/html/outreach.html

Please study this information carefully.