Strange Quarks

• What are strange particles composed of?

  Strange or anti-strange quarks
• What are the characteristics of strange particles?

  • Produced through strong interaction
  • Decay through weak interaction
  • Produced in quark-antiquark pairs
• How are kaons produced?

  Through the strong interaction
• What particle is involved in kaon production?

  The gluon exchange particle

  
• How do kaons decay?

  Via the weak interaction

  
• What particle is involved in kaon decay?

  The W boson

  
• What is strangeness in particle physics?

  A quantum number like baryon number

  
• When is strangeness conserved?

  In every interaction except weak interaction
• Why are strange particles produced in pairs?

  Because strangeness is conserved
• What is the strangeness value for particles with an anti-strange quark?

  S = +1

  
• What is the strangeness value for particles with a strange quark?

  S = -1

  
• What is the strangeness value for particles with no strange quark?

  S = 0

  
• Which particles can have strangeness values of +1 or -1?

  Only particles with a strange quark
• How can strangeness change in weak interactions?

  By 0, +1, or -1
• How can you prove a decay is via weak interaction using strangeness?

  1. Determine strangeness of each particle.
  2. Compare strangeness on both sides.
  3. Comment on conservation of strangeness.
• What is the strangeness of the sigma baryon with quark structure suu?

  S = -1
• What is the strangeness of a proton and pion?

  S = 0
• What does it indicate if strangeness is not conserved in a decay?

  It indicates a weak interaction
• Why is strangeness not conserved in weak interactions?

  Because weak interactions allow strangeness change