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: 1-7

Study Points

• 32.1 High energy interactions between atoms, or their subparticles protons, neutrons, and electrons, reveal the existence of other subparticles. To produce these collisions, physicists accelerate charged particles (protons and electrons) in magnetic fields generated in cyclotrons, synchrotrons, and linear accelerators. By crossing beams of accelerated particles, physicists at CERN can fracture subatomic particles into constituent components.
• 32.2 Feynman diagrams are used to explain how two particles interact by creating EM fields that affect each other, or by exchanging photons. Each force is associated with a particle: electromagnetic force with photons, strong nuclear force with mesons, and weak nuclear forces by W⁺, W^-, and Z⁰. Gravitational force is associated with the graviton, a particle which has not been observed.
• 32.3 All particles have corresponding antiparticles, which have the same mass as their corresponding particle, but the opposite charge except for the Higgs bosun and the photon are their own antiparticles. The current universe lacks antiparticles in quantity.
• 32.4 As with other interactions where energy is exchanged and conserved, particle interactions conserve specific characteristics, such as the baryon number and lepton numbers (along with energy and momentum, of course).
• 32.5 Neutrinos are low-to-no nass particles that can be detected through their weak interactions with heavy particles.
• 32.6 Particles are classified as
  • Fundamental particles
    • gauge bosons (gluons, photons, W, Z particles) which mediate fundamental forces
    • Higgs boson (produces mass)
    • Leptons (electrons, neutrinos, muons)
    • Quarks
  • hadrons
    • mesons (quark + antiquark)
    • baryons (3 quarks - proton, neutron, etc.)
  Particles can decay from one form to one or more others as long as key characteristics are conserved.
• 32.7 Particles are considered stable if they last for a long time, but most subatomic particles produced by collisions decay quickly to other particles.

Key Equations

Web Lecture

Read the following weblecture before chat: Subatomic Particle Interactions

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

• The chapter quiz is not yet due.

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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