Agenda

Course Plan

You may refer to the Winter 2020 course for a sense of the topics, level, and style of the course.

Written course notes are posted in links below. I am gradually combining these into typed notes here, but there may be a delay. You are especially encouraged to contribute if you are familiar with GitHub and LaTeX. 

• Course Notes from 2017 by Adam Green

• Course Notes from 2020

Week 4: Non-Abelian Gauge Theories... indexology

• Lecture 7: cross sections, by Adam Green

• Lecture 8: Indices, symmetries, generators, and gauge symmetries

Homework: all assignments due Thursday

• Short homework, due Thursday, 4/21: momentum flow, QED+muon. Submission link.

• Long homework due Thursday, 4/28. Submission link.

• Explainer Video Assignments, the number under "LHW2 Explainer" is the problem that you should prepare an explainer video on. Some of the problems appear long and have multiple parts! Give the most time to the most significant parts of the problem. You can assume that people looking at your video have done earlier problems. Submission link.

• Bug bounty: extra credit for the first person to catch a mistake and email the professor about it. Amount of the extra credit depends on the egregiousness of the mistake and how quickly it is caught.

Reading

• Larkoski, Chapter 3 (group theory), 11

• Introduction to Tensor Calculus, Dullemond and Peeters

• "Tensors: A guide for undergraduate students," Franco Battaglia American Journal of Physics 81, 498 (2013) 

• A Student's Guide to Vectors and Tensors, Fleish

Week 5: Electroweak Theory, Unbroken Phase

Note: Adam Green will have online office hours on Wednesday. 

• Lecture 9: The index structure of weak theory, order parameters of symmetry breaking

  • Comment: today we talked about the muon/neutron lifetime problem on the long homework. Many thanks for those who pointed out a key flaw. When you put in the numbers, the muon lifetime is off by around four orders of magnitude. I did a quick check, and this seems to come from five powers of (2π) that should be in the denominator. These factors come from the phase space integral: three final state momenta and an overall four-momentum conserving δ-function. 

• Lecture 10: Electroweak lepton sector

Homework: all assignments due Thursday

Long Homework 2 and the explainer video are due this Thursday 4/28. 

• Short homework, due Thursday, 4/28: SU(2) invariants. Submission link.

• No long homework this week. Please catch up on the assignments.

• Explainer video assignments: no assignments this week, please catch up on the assignments.

Reading

• Larkoski, Chapter 3 (group theory), 11

• Introduction to Tensor Calculus, Dullemond and Peeters

• "Tensors: A guide for undergraduate students," Franco Battaglia American Journal of Physics 81, 498 (2013) 

• A Student's Guide to Vectors and Tensors, Fleish

Week 6: Electroweak Theory, Unbroken Phase

• Lecture 11: spin, the Standard Model quantum numbers. 

• Lecture 12: Yukawa interactions, spin indices

Reading: indices of particle physics

• "What is Spin?," Ohanian. American Journal of Physics, 54, 500 (1986). 

• Particle Physics: A Los Alamos Primer

  • See: "Particle Physics & the Standard Model," Raby, Slansky, West

  • See: "Lecture Notes: from simple field theories to the Standard Model," Slansky

• Sci-Am: "A Unified Theory of Elementary Particles and Forces," Georgi (this one is really good). You may need use the UCR Library VPN to access this.

• Sci-Am: "Gauge Theories of the Forces between Elementary Particles," 't Hooft (A large number of pages are made up of advertising from the early 80s). You may want to use the UCR Library VPN to access this.

• Tully, Elementary Particle Physics in a Nutshell. Several of the topics that we cover are in this book, but at significantly more mathematical depth. 

Reading: feynman diagrams

• Feynman Diagrams, A. Barr

• "Physics and Feynman Diagrams," Kaiser

Reading: general tensors

• Schwitzenberg, Physics from Symmetry. For those who want an introduction to group theory from a physics perspective, this may be a good starting place. 

• Larkoski, Chapter 3 (group theory), 11

• Introduction to Tensor Calculus, Dullemond and Peeters

• "Tensors: A guide for undergraduate students," Franco Battaglia American Journal of Physics 81, 498 (2013) 

• A Student's Guide to Vectors and Tensors, Fleish

Link to grade sheet. Please check your email for your code. The grades are not normalized.

Homework: all assignments due Thursday

Long Homework 2 and the explainer video are due this Thursday 5/5. 

• Short homework, due Thursday, 5/5: fundamental interactions. Submission link.

• Peer Review Assignments, due Thursday 5/12. Please watch the videos and fill out the peer review form. Please fill out the link for each of the two assignments that you are reviewing. Do not forget to email a copy of your review to your reviewee.

• No long homework this week. Please catch up on the assignments.

• Explainer video assignments: no assignments this week, please catch up on the assignments.

Week 7: Breaking Electroweak Theory

• Lecture 13: On the unbearable masslessness of the Standard Model.

• Lecture 14: electroweak symmetry breaking. (Apologies, no notes today.)

Homework

• Short homework 7, due Thursday 5/12. Equations of motion, masses, and the trouble with fermion masses. Submission link.

• Long homework, due Thursday 5/26. The Higgs vev, electroweak symmetry breaking, flavor. Submission link.

Week 8: Electromagnetism, finally

• Lecture 15: Electromagnetism from electroweak symmetry breaking

• Lecture 16: Kinematics meets dynamics: counting degrees of freedom for massive particles. Flavor symmetry

  • We were pretty quick in our study of flavor physics. You can find more details in these lecture notes that were named after a restaurant I used to frequent. 

Field Theory Suggestions

In class on Thursday we had a mini discussion on recommended quantum field theory texts. Here are some suggestions:

• David Tong's lecture notes (I suggest starting here)

• Zee's Quantum Field Theory in a Nutshell is rigorous but has a conversational (and insightful) tone

• I've heard good things about No-Nonsense Quantum Field Theory: A Student-Friendly Introduction by Schwitzenberg. You may also like Schwitzenberg's textbook on symmetry (referenced above)

• QFT for the Gifted Amateur by Blundell and Lancaster is also very beginner-friendly

• Peskin's Introduction to Particle Physics book has a dose of field theory in it, and is firmly rooted in the experimental foundations of the Standard Model. 

• I have heard positive things about LaBelle's Supersymmetry DeMystiFied as an introduction to spin-1/2 representations.

Homework

• Short homework 8, due Thursday 5/19. Electromagnetism. Submission link. Updated 5/17, 7pm. Thanks Robert V. 

  • Hint, to address some of the factors of 2 that I messed up.

• Long homework, due Thursday 5/26. The Higgs vev, electroweak symmetry breaking, flavor. Submission link.

Week 9: An overview of advanced topics in field theory

• Lecture 17: Loop diagrams and renormalizability

  • See suggested field theory references from last week

  • Reading: John Baez's post on renormalizability (2006) and renormalization (2009); and a bit on the Callan-Symanzik equation

  • One of my favorite descriptions of renormalization and the relation to dimensional analysis is "Dimensional Analysis in Field Theory" by Stevenson

  • Popular description of renormalization by Charlie Wood in Quanta magazine.

  • A nice description of renormalization from ZAP Physics on YouTube; though I warn that the point of renormalization is not to "deal with infinities." Those infinites were never physical to begin with. Renormalization is the idea that the "best" perturbative description of a quantum field theory changes depending on the scale at which you are testing the theory.

• Lecture 18: The Hierarchy Problem of the Standard Model

  • Today's colloquium will be on the Hierarchy Problem!  3:40 PM in 138 Winston Chung Hall. Cookies at 3pm in the Barkas Lounge. 

Homework

• Short homework 9, due Thursday 5/26. Electromagnetism. Submission link. 

• Long homework, due Thursday 5/26. The Higgs vev, electroweak symmetry breaking, flavor. Submission link.

Beyond the Standard Model

• Lecture 19: review of the "18 parameters" of the Standard Model, the nineteenth parameter, and some reasons to suspect that there's more.

  • "The eighteen arbitrary parameters of the Standard Model in your everyday life." Robert Cahn (1996). Now that we've reviewed the Standard Model, you should think about how many free parameters there are, and what the universe would have looked like if they were different.

  • BobbyBroccoli has a series of three mini-documentaries on the Super Conducting Supercollider (SSC), the failed American 40 TeV collider. Part 1, Part 2, Part 3. It is a fascinating take on the recent history of particle physics in the United States.

    • The documentaries draw on the definitive book on the topic, Tunnel Visions. You can find a couple of colloquia by the authors here and here.

    • If you want to learn more about the future of particle physics, you should learn about the ongoing Snowmass 2021 process. You can find highlights from the theoretical physics frontier here

  • "Regularization, renormalization, and dimensional analysis: Dimensional regularization meets freshman E&M," Fredrick Olness and Randall Scalise
    American Journal of Physics 79, 306 (2011); https://doi.org/10.1119/1.3535586

    • This is an excellent introduction to the ideas of renormalization applied to a system that has nothing to do with quantum field theory. The article will seem a little strange: it asks questions in a way that is not common in your electrodynamics courses because it approaches this familiar topic using the methods that we use in quantum field theory.

  • Not directly related to our course, but one question that came up during our discussions was the twin paradox in a closed universe. I highly recommend Jeff Weeks' summary in the The American Mathematical Monthly (Vol 108 p. 585, 2001) .

• Lecture 20: we discussed neutrino oscillations, the 18 (really 19) parameters of the Standard Model (see Lec 19 notes), and 

Homework

• Short homework 10, due Thursday 6/2. A brief example of renormalization conditions. Note: this is a technical topic, but the actual steps should be trivial. The goal of the short homework is just to show how this simple idea is sometimes lost because of all the technical mathematics surrounding it in a typical quantum field theory calculation. Submission link.