Particle Physics Questions
Q6.
(a) The Σ+ particle is a baryon with strangeness –1.
(i) How many quarks does the Σ+ particle contain? Three![](../../../graphics/symbols/nuclides/ticksmall.png)
(1 mark)
(ii) How many of the quarks are strange? One ![](../../../graphics/symbols/nuclides/ticksmall.png)
(1 mark)
(b) The Σ+ decays in the following reaction
Σ+ → π+ + n
(i) State two quantities that are conserved in this reaction.
Charge
Baryon number
Lepton number
Mass
Energy
Momentum
Maximum 2 marks
(2 marks)
(ii) State a quantity that is not conserved in this reaction.
Strangeness ![](../../../graphics/symbols/nuclides/ticksmall.png)
(1 mark)
(iii) What interaction is responsible for this reaction?
Weak Interaction
(1 mark)
(iv) Into what particle will the neutron formed in this reaction eventually decay?
proton ![](../../../graphics/symbols/nuclides/ticksmall.png)
(1 mark)
(Total 7 marks)