Q8 · 2025 · Paper 2Simple familiar4 marks
QUESTION 8 (4 marks)
A Feynman diagram is shown.
a)[1 mark]
Identify the two quarks that are present in the diagram.
b)[1 mark]
Deduce the boson involved in the interaction.
c)[2 marks]
Describe the significance of symmetry in particle interactions.
WORKED SOLUTION
4 marksQCAA guide · typeset solution
ANSWER
See worked solution below.
Worked solution
a)
1. up quark
2. down quark
b) W boson
c) Symmetry in particle interactions means that the particles follow conservation laws, in particular baryon and lepton numbers. This means that predictions about the particles that are produced can be made.
identifies up quark and down quark
identifies W boson
describes conservation of baryon and lepton numbers
describes that the produced particles can be predicted
One QCAA sample method typeset for web; criterion wording is adapted from the official marking guide.
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