PHYS 165

Introduction to Particle Physics


Introduction to Particle Physics

Physics 165: Introduction to Particle Physics. 4 Units. Prerequisite: Physics 156A (Quantum Mechanics)

Prof. Flip Tanedo (Physics 3053 / flip.tanedo@ucr.edu)

TA: Kuntal Pal (kpal002@ucr.edu)

Meeting time: Tuesdays and Thursdays, 2:00 - 3:20pm

We will not use the designated discussion section hour (Wednesday, 7:00 - 7:50pm).

This is an introduction to elementary particle physics, the study of the fundamental constituents of matter and the forces that dictate their interactions. We focus on building a theoretical understanding of the Standard Model of particle physics based on Feynman diagrams. We will cover kinematics, what it means to have a theory of particle physics, how we perform experiments in particle physics, and what the future holds.

Syllabus

Details about course procedures, evaluation, and plans are available in the syllabus (markdown version).

Resources

  • The primary textbook is Elementary Particle Physics: An Intuitive Introduction by Larkoski.
  • Past students have also enjoyed supplementing the course with The Standard Model in a Nutshell, by Goldberg.
  • A text with more of an experimental emphasis is Introduction to Elementary Particle Physics, by Bettini.
  • Another recent textbook is Concepts of Elementary Particle Physics by Peskin.
  • Seiden's Particle Physics: A Comprehensive Introduction
  • Griffith's Introduction to Elementary Particles
  • 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

Homework

Short homework is due on the Thursday after it is assigned, two days later. The long homework is due 2 weeks later on Tuesday. (More about "asymmetric homework.")

  • HW1 short (Due Thursday, Jan 16): units
  • HW1 long (Due Tuesday, Jan 28): kinematics and QED
  • HW2 short (Due Thursday, Jan 30): momentum flow
  • HW2 long (Due Tuesday, Feb 11): indices. Indices everywhere.
  • HW3 short (Due Thursday, Feb 13): mass
  • HW3 long (Due Tue, Feb 25): symmetry breaking
  • HW4 short (Due Thu, Feb 27): flavor
  • HW4 long (Due Tue, Mar 10): flavor (note: version distributed in class is incorrectly listed as "short" homework and problem 5 should be marked extra credit.)
  • HW5 (Due Mar 13 officially): you should be able to complete this on one sheet of paper. You may submit it in Prof. Tanedo's mailbox in Barkas lounge or digitally via e-mail. If submitting by e-mail, please send to both Prof. Tanedo and Kuntal, and include "P165" in the subject line.

Weekly Schedule

To be updated with links to notes as we go. If I'm behind on updating this page, notes are uploaded to GitHub here.

  1. Introduction: dimensional analysis, kinematics, dynamics, the Feynman rule game.
    • Lec 1: Welcome, dimensional analysis, kinematics vs. dynamics
    • Lec 2: How to play the Feynman game
  2. Quantum Electrodynamics and its variants
    • Lec 3: Quantum mechanics of Feynman diagrams, kinematics
    • Lec 4: Kinematics, indexology part I
      • Additional reading: Griffiths, chapter 3; Larkoski chapters 2.1 and 3
  3. Putting it all together, experiments in particle physics
    • Lec 5: Weak force, indexology part II -- electric charge
      • Additional material: see Goldberg, The Standard Model in a Nutshell, chapter 1 on special relativity and tensors. This is available on our iLearn page.
      • In slightly more depth, you can review my P231 review lectures on linear algebra and indices: Part I (P231-2017, Lec 3), Part II (P231-2017, Lec 4)
    • Lec 6: Cross sections (Kuntal Pal); see Larkoski for additional reading
  4. Symmetry, tensors, and indices
    • Lec 7: Indexology, part III: indices for special relativity
    • Lec 8: Indexology, part IV: weak and electroweak
  5. Unified electroweak theory
  6. The Higgs
  7. Electroweak symmetry breaking
  8. The Higgs Mechanism
    • Lec 15: Spin-1, Higgs Mechanism, the "eating" of degrees of freedom
    • Lec 16: Flavor Indices (see Lec 15 notes)
  9. Flavor Physics
  10. Beyond the Standard Model
    • Lec 19: Thoughts on the Hierarchy Problem
      • Regarding the Standard Model parameters: Cahn, "The eighteen arbitrary parameters of the standard model in your everyday life," Rev. Mod. Phys. 68, 951.

Projects

Students are required to give a 5 minute (strict) presentation on an experiment in particle physics. The criteria are:

  1. Introduce the experiment to your classmate. What is the question it is trying to answer?
  2. Show the relevant Feynman diagram for the experiment.
  3. Show one plot (sketch it on the board) and explain it. What is the x axis? What is the y axis? What do we expect from our hypothesis? What does the data show? What does it mean if a curve is going up or down? What does it mean if a curve has an extremum?

Note that not all particle physics experiments are colliders! Also, large "general purpose" collaborations like CMS and ATLAS actually do many types of experiments ("searches"). For this project, please focus on one experiment (one plot). For example, you can present how CMS discovered the Higgs boson in the two-photon channel, but not "CMS studies particle physics by smashing protons together."

You should try to learn about the experiment from the public website or public-level explainers.

Other experiments:

Useful Links

  • 2018 Course (contains separate set of lecture notes, homework will be similar)
  • Particle Data Group (PDG), compendium of everything we know about particle physics