Mesons

• What are the three types of pions?

  Positive, negative, and neutral pions
• What is the relationship between a positive pion and a negative pion?

  The negative pion is the anti-particle of the positive pion
• What is unique about the neutral pion?

  The neutral pion is its own anti-particle
• Why are pions considered more stable than other mesons?

  They are the lightest mesons
• Where were pions originally discovered?

  In cosmic rays
• What role does the strong nuclear force play in a nucleus?

  It keeps protons and neutrons bound together
• What is the exchange particle of the strong nuclear force?

  The pion
• How is the strong force transmitted between protons and neutrons?

  By the exchange of a pion

  
• What does it mean that pions mediate the strong nuclear force?

  Pions bring about the strong nuclear force
• Why is the pion created during the strong force interaction considered a virtual particle?

  It temporarily violates energy and mass conservation
• What is the role of gluons in the strong interaction?

  They bind quarks together
• How do pions and gluons differ in their roles?

  Pions bind nucleons; gluons bind quarks
• What are the characteristics of kaons?

  • Can be positive, negative, or neutral
  • The anti-particle of positive kaon is negative kaon
  • The neutral kaon is its own anti-particle
• How are kaons produced?

  By strong interaction between pions and protons

  
• What happens to kaons due to their instability?

  They normally decay into pions
• Why do kaons have unusually long lifetimes?

  They contain a strange quark
• Through which interaction do kaons decay?

  Through the weak interaction
• What should you remember about pions for your exam?

  • Pion is the exchange particle of the strong nuclear force
  • Gluons may also be accepted as mediators