Particle Physics Questions
Q5.
(a) Mesons that contain a strange (or antistrange) quark are known as K-mesons or kaons. Mesons are a sub-group of a larger group of particles.
(i) State the name of this larger group of particles.
Hadrons 
(1 mark)
(ii) Determine the charge on a kaon with a quark structure of u̅ s

-2/3 e + -1/3e = -1e 
(1 mark)
(b) A proposed decay for this kaon is
̅u s → µ+ + vµ
(i) Apply the law of conservation of strangeness to the proposed decay.
1 → 0 + 0 
Strangeness is not conserved
(1 mark)
(ii) Comment on whether or not this decay is possible.
Strangeness is not conserved but decay is possible because it is a decay that proceeds via the weak nuclear force. 
(1 mark)
(Total 4 marks)