Particle Questions that include Feynman Diagrams
Q7.
(a) The negative kaon, K–, has a strangeness of –1. Write down its quark composition.
(2 marks)
(b) The kaon, K– may decay into a muon and an antineutrino in the following way: 
(i) Complete the following table using ticks and crosses as indicated in the first row.
|
K– |
μ– |
ν μ |
charged particle |

|

|
X |
hadron |
|
|
|
meson |
|
|
|
baryon |
|
|
|
lepton |
|
|
|
(ii) In the decay shown above, charge is conserved. Give another quantity that is conserved and a quantity that is not conserved in the decay of K–.
quantity conserved ..........................................................................................
quantity not conserved ...................................................................................
(6 marks)
(c) The Feynman diagram below represents the β+ decay process.

(i) What quantity changes continuously in moving from the bottom to the top of the diagram?
(ii) Name the particles represented by the letters A to D.
(iii) What type of interaction is responsible for β+ decay?
(6 marks)
(Total 14 marks)
