Q28 · 2023 · Paper 1Simple familiar2 marks
QUESTION 28 (2 marks)
The Feynman diagram for a neutron decaying into a proton and electron is shown.
Describe the significance of the electron antineutrino in this particle interaction.
WORKED SOLUTION
2 marksQCAA guide · typeset solution
ANSWER
See worked solution below.
Worked solution
Sample response The
The law of conservation requires the baryon and lepton numbers | « id
to be conserved during a particle interaction. The electron sy
antineutrino is required to maintain symmetry for this interaction. | . de
The law of conservation also requires mass to be conserved so
an antineutrino is required to ensure this.
e identifies conservation of lepton number /
symmetry of the interaction [1 mark]
e describes conservation of mass [1 mark]
One QCAA sample method typeset for web; criterion wording is adapted from the official marking guide.
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