Particle Physics: Discovering and Describing Particle Interactions

Homework

• Reading Preparation
• Key Equations
• WebLecture
• Study Activity
• Chat Preparation Activities
• Chapter Quiz
• Lab Work

Reading Preparation

Text Reading: Giancoli, Physics - Principles with Applications, Chapter 32: 8-12

Study Points

Study Points

Text Reading: Giancoli, Physics - Principles with Applications, Chapter 32: sections 8 to 12

• 32.8 New patterns of behavior led to identification of new conserved characteristics, which, since they have no analogy in common experience, have odd names: strangeness and charm.
• 32.9 To explain the wide variety of hadron behaviors, M. Gell-Mann proposed the existence of quarks, which combine to form the other subatomic particles. Quarks are distinguished by their mass, charge, baryon number, strangeness, charm, and top or bottom characteristics. Different behaviors of mesons can be explained by quark-antiquark paris, those of baryons by combinations of three quarks. Quarks, together with gauge bosons, the Higgs boson, and leptons are "fundamental", since hadrons are made of quarks.
• 32.10 The Standard model uses further quark characteristics (color and flavor) to associate specific behaviors with quark types. Other classifications emphasize whether particles follow the Pauli exclusion principle and have half-integer spins (Fermions) or violate the principle and have integer spins (bosons). Using color distinctions prevents quarks from violating the principle and maes them fermions. Quarks have not been observed in isolation, only in combinations. This quantum chromodynamics (QDC) theory, together with the theory that the electromagnetic force and weak nuclear force can be combined (the electroweak theory) make up the Standard Model.
• 32.11 One goal of modern physics is to find a way to understand the four fundamental forces as a single force in a grand unified field theory. The event which split the forces apart during the early universe is cause the symmetry-breaking event. Amont the predictions of the GUT is that photons will eventually decay, but the period is on the order of the age of the universe. Other problems the GUT must address is the matter-antimatter issue: why is there so little antimatter in the current universe?
• 32.12 Alternatives to the Standard Model include string theory, in which the fundamental entities are not particles with masses in a confined volume, but strings vibrating with different patterns; and supersymmetry theories (SUSY). Each of these alternatives address problems in the Standard Model, but fail to address other issues.

Key Equations

Web Lecture

Read the following weblecture before chat: The Standard Model

Study Activity

Chat Preparation Activities

• Forum question: The Moodle forum for the session will assign a specific study question for you to prepare for chat. You need to read this question and post your answer before chat starts for this session.
• Mastery Exercise: The Moodle Mastery exercise for the chapter will contain sections related to our chat topic. Try to complete these before the chat starts, so that you can ask questions.

Chapter Quiz

• Required: Complete the Mastery exercise with a passing score of 85% or better.
• Go to the Moodle and take the quiz for this chat session to see how much you already know about astronomy!

Lab Work

If you want lab credit for this course, you must complete at least 18 labs; you may complete more if you are preparing for the AP exam.. One or more lab exercises are posted for each chapter as part of the homework assignment. We will be reviewing lab work at regular intervals, so do not get behind!

• Lab Instructions: Cloud Chamber

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