Particle Questions that include Feynman Diagrams

Q8. A positron is emitted from a nucleus when a proton changes to a neutron in the nucleus.

The Feynman diagram for the quark interaction is shown in the diagram.

(a) Identify the particles labelled A, B, C and D in the diagram.

(3 marks)

(b)

(i) State the interaction responsible for this process.

(1 mark)

(ii) State which letter in the diagram above represents an exchange particle.

(1 mark)

(iii) State one difference between this exchange particle and a photon.

(1 mark)

(c) Energy and momentum have to be conserved in this process.

State two other quantities that need to be conserved and show that they are conserved in the process.

(4 marks)

(Total 10 marks)