Physics 226

Particles and Symmetries

Autumn 2014



Stephen D. Ellis (


PAB B401

Office hours:

 Tues 12/11/14, 3:45 – 5 PM PAB405


12:30-1:20 PM, MWF, room PAA 110

Higgs bump in CMS diphoton mass distribution 




Particle Physics in the News

Atlas detector at LHCSimulated black hole production
    in the Atlas detector at LHCRecent particle physics related articles
Webpage for movie Particle Fever  (the movie)

Latest results from Planck space telescope (12/2/14)
Muons to study volcanoes (12/2/14)
Wanted – Higgs Hunters (scan ATLAS data) (11/26/14)
Discussion of the Science in “Interstellar” (11/26/14)
More about the “Science of Interstellar” (11/24/14)
Video discussion of Dark Matter experiments (11/20/14)
New baryons found with quark content bds (11/19/14)
Dark Matter: Out with the WIMPS, in with the SIMPS (10/30/14)
Supernova shock waves create glowing arcs across sky (10/30/14)
Science is hard – More on Ripples (5/29/14)
Measuring the proton’s magnetic moment (5/29/14)
Ripples from the Big Bang (3/24/14)

Space Ripples Reveal Big Bang’s Smoking Gun  (3/17/14)
Why particle physics matters  (9/10/13)
Dark Energy Survey  (9/7/13)
AMS: antimatter in space  (4/3/13)
Chasing the Higgs  (3/5/13)
Search for the Higgs boson at the LHC reveals new particle  (7/4/12)
Daya Bay: Neutrino oscillations and ϑ13  (3/8/12)
Superluminal neutrinos? (not!)  (2/22/12)
Natural particle collider in space  (8/21/12)


The Illustris Project to calculate/simulate the history of the Universe (watch the movie!)

A video of the UW HEP Group’s presentations at the “Higgs Night Out” held at T.S. McHugh's
on the evening of 7/3/12 can be found at

Here is a talk introducing the LHC and the Higgs boson presented at the San Juan Nature Institute (2/27/14).

Here are (URL) links to most of the videos we view before the start of class.

Inside the Super-Kamiokande neutrino detector 

Class Overview

Candidate double Z-boson event
    from the CDF experiment at FermilabThis course provides an introduction to the fundamental constituents of matter and the symmetries which characterize their interactions. Topics include the fundamental symmetries of nature (such as Lorentz invariance, CPT, and baryon and lepton number conservation), the "building blocks" of the current Standard Model of nuclear and particle physics (for example, quarks, gluons and leptons), the importance of symmetries in characterizing the interactions of particles, and the key experimental evidence on which the Standard Model is based.


Course Objectives

Atlas detector schematicLike most physics courses, the “big picture” goals in this course are two-fold: to acquire knowledge about physical aspects of the universe we live in and to learn to quantitatively analyze physical systems, i.e., solve problems.  More specifically, students will acquire practical facility with special relativity and its application to relativistic particle dynamics.  They will learn to be able to identify various classes of elementary particles and predict the type of interactions responsible for their decays and scatterings.  They will practice performing order-of magnitude estimates relevant for interpreting and/or judging the feasibility of a variety of modern physics experiments.  Along the way, we will attempt to pay close attention to new results coming from the LHC at CERN, e.g., results on the Higgs boson.  (For the latest LHC news go to the LPCC.) 

The course covers material from several different, but related, subject areas.  The primary reference is the course notes, accessible below.  Students will be expected to master the material in these notes (and the quizzes are intended to encourage you to stay up-to-date).  Carefully studying the notes, including the worked examples at the end of the chapters, is essential for success in this class.  Do the reading before class and come prepared to ask questions about any confusing issues.  There are no required textbooks, only recommended supplemental texts.

While some of the homework exercises are typical textbook style problems, they are generally not of the variety “plug these numbers into Equation 6”, but rather the homework exercises focus on analyzing interesting, but often unfamiliar, physical systems using the principles and techniques discussed in this course (and its prerequisites).  The HW should be thought of as (the often requested) practice exams.



2014 Tentative syllabus

Week 1:   Introduction, Math Physics Review and Special Relativity
Week 2:   Spacetime physics
Week 3:   Relativistic dynamics

Week 4:   QM Review, Known particles and interactions
Week 5:   Known particles and interactions, Quarks and mesons

Week 6:   Baryons

Week 7:   Symmetries

Week 8:   Isospin

Week 9:   Discrete symmetries
Week 10: Force carriers and the Standard Model


2014 (Autumn) Class notes (link for the complete set with table of contents and index)

Chapter 0: Introduction
Chapter 1: Math methods
Chapter 2: Special relativity
Chapter 3: Minkowski spacetime

Chapter 4: Relativistic Dynamics
Chapter 5: QM and Angular Momentum
Chapter 6: Known particles
Chapter 7: Quarks and hadrons
Chapter 8: Symmetries

Chapter 9: Weak Interactions


Chapter 10: Intro to Group Theory

Chapter 11: Young Diagrams and SU(N) Representations


Event with large missing
    (unobserved) energy from the Dzero experiment at Fermilab




Muon neutrino event at Super-Kamiokande
There will be weekly homework assignments, one midterm, and a final exam. There will also be regular “clicker quizzes” during lecture. Grades will be based approximately 30% on homework, 10% on quizzes, 20% on the midterm, and 40% on the final.  The final exam is a required part of the course

HW must be turned-in (either in class or in Prof. Ellis’ mailbox) by the end of class on the due date, typically a Wednesday (except after Thanksgiving when we move to Friday).  Late HW with a 50% discount in points is allowed if turned-in (in class or in Ellis’ mailbox) by the end of class on the class-day following the original due date (so typically a Friday—note this does not apply to the last HW as there is no following class-day).  To control the amount of paper handling the late option CANNOT be applied to part of an assignment.  A late assignment is accepted only if NO part of the assignment was turned in on-time.  To facilitate the substantial paper handling inherent in this system requires that HW be turned in on standard size, 8.5x11 inch paper, stapled in the upper left-hand corner.  (Accurately handling a stack of paper involving 8x10 or 10x12 inch paper along with 8.5x11 is just too time consuming.)  HW on pages torn from a spiral notebook, with the associated ragged edge, will also not be accepted.  Students periodically attempt to submit HW via email.  I will only accept complete HW sets as a single, easily legible PDF file.  Note that your cellphone does not really work well as a scanner.

Scores on quizzes, HW assignments and the MidTerm Exam can be seen on the Catalyst gradebook.  Post-midterm the column labeled Projected Score is calculated assuming that the average (percentage) scores on the remaining HW assignments are identical to those on the previous assignments and that the (percentage) grade on the Final Exam is identical to that on the MidTerm Exam.  The Projected Grade is a “flat” (i.e., not highly curved) mapping of the scores onto the range 0.0 to 4.0 such that the highest score yields a 4.0 grade and that passing (a grade of 2.0) comes from a score of approximately 40%.  This is just an estimate of the Final Grade.  The total score and the grading algorithm will “mature” as more information becomes available.  It is to everyone’s advantage to learn from the HW sets and do well on the Exams and quizzes. 


Prerequisites – successful completion of Phys 121-3, 225 (Quantum I) and 227 (Elementary Mathematical Physics I); Phys 228 is recommended.  We will briefly discuss the most relevant subjects from Phys. 227 and 225 in Lectures 1 and 5.  Students are also encouraged to review the content of all of Phys. 227 in the Lecture Notes from the last time I taught that course (2008), which are available here.

It is expected that students entering Phys 226 have some working knowledge of special relativity and quantum mechanics.  Some facility with the following is assumed: complex variables and complex arithmetic, harmonic (sines & cosines) and hyperbolic (sinh & cosh) functions, simple transformations represented by matrices operating on vectors or state vectors (including bras and kets), quantum numbers, eigenvalues and eigenstates (in the context of quantum mechanics), quantized spin in simple systems (e.g., spin ½ or related 2-state systems), symmetries and conserved quantum numbers.

For in-class use, students must have an H-ITT radio-frequency clicker, available new from the UBookstore, or sometimes used from sellers on Amazon or Ebay. Be sure to get the RF version: model TX3100 or TX3200.  Clicker quizzes will begin by the beginning of the second week of classes and occur regularly thereafter.




The course notes are the primary reference for this class, but these books may also be useful:
Introduction to Relativity by John B. Kogut
Introduction to Nuclear and Particle Physics by A. Das and T. Ferbel



Reading Assignments

Please read prior to the indicated week: (Note Tuesday, November 11 and Friday, November 28 are UW holidays)



Course notes


Sep 24 - 26

chapters 0, 1 & 2

Kogut: chapter 1 & 2

Sep 29 – Oct 3

chapters 2 & 3

Kogut: chapter 3 & 4

Oct 6 – 10

chapters 4 & 5

Kogut: chapter 4

Oct 13 - 17

chapters 5 & 6

Kogut: chapter 6, Das & Ferbel: sections 4.1-4.4 (don't worry about last 1.5 pages)

Oct 20 - 24

chapter 6

Das & Ferbel: sections 9.1 - 9.4.3

Oct 27 - 31

chapter 7


Nov 3 - 7

chapter 7 and Midterm

Das & Ferbel: sections 9.4.4 - 9.8, 10.4

Nov 10 - 14

finish chapter 7

Das & Ferbel: section 10.5, chapter 11

Nov 17 - 21

chapter 8

Das & Ferbel  chapter 13

Nov 24 - 28

finish 8 and start 9

Das & Ferbel: sections 13.1 - 13.9



Dec 1 – 5                            finish chapter 9


Homework Assignments  (assignments and solutions posted on Catalyst)

Problem Set #1     (10/1/14)

Problem Set #2     (10/8/14)


Problem Set #3     (10/15/10)


Problem Set #4     (10/22/14)


Problem Set #5      (10/29/14)


Problem Set #6      (11/5/14)


Problem Set #7      (11/12/14)
                                                      Extra Credit HW    (11/17/14)


Problem Set #8      (11/19/14)


Problem Set #9      (11/26/14)


Problem Set #10    (Due 12/5/14)    




· Midterm: tentatively scheduled for Friday, November 7, 2014, in class (A110);  

· Final:  Thursday, December 11, 2014 , 8:30 to 10:20 AM in A110;

Exams will be closed book, closed notes, but a summary sheet will be provided.
The MidTerm summary sheet is here.  The final summary sheet is here.  Calculators (but not cellphones) allowed.


Useful Resources

Particle Data Group: Constants, Units, Atomic and Nuclear Properties

Particle Data Group: Summary Tables of Particle Properties

Particle Adventure (a breezy interactive tour from the Particle Data Group)

The LHC (introductory videos)

Interactive Table of Nuclides from the Korea Atomic Energy Research Institute

Interactive Chart of Nuclides from the National Nuclear Data Center at BNL


1964 Messenger Lectures by Richard Feynman at




Aerial view of the south pole
    showing the IceCube neutrino experiment under construction


Superconducting RF cavity
    developed for the proposed International Linear Collider


Au+Au relativistic heavy ion collision
    observed by the STAR detector at RHIC