A negative pion collides with a proton and the following interaction is observed:
π−+p→K0+Λ0 \pi^- + \text{p} \to \text{K}^0 + \Lambda^0 π−+p→K0+Λ0Λ0\Lambda^0Λ0 is a neutral lambda particle with a strangeness of −1-1−1.
The interaction can be used to deduce the classifications of the Λ0\Lambda^0Λ0.
Identify the classifications of each particle by completing the table below. Place a tick (✓\checkmark✓) in the appropriate boxes for each particle.
| Particle | Baryon | Hadron | Lepton | Meson |
|---|---|---|---|---|
| π−\pi^-π− | ||||
| p\text{p}p | ||||
| K0\text{K}^0K0 | ||||
| Λ0\Lambda^0Λ0 |
A conservation rule predicts that the following interaction cannot occur:
π−+p→Kˉ0+Λ0 \pi^- + \text{p} \to \bar{\text{K}}^0 + \Lambda^0 π−+p→Kˉ0+Λ0State the conservation rule and explain your answer.
One way in which neutral eta mesons decay is:
η0→e−+e++γ \eta^0 \to \text{e}^- + \text{e}^+ + \gamma η0→e−+e++γCompare the rest energies of the particles involved in this decay.
The decay of the neutral eta meson leads to the production of further gamma photons. Explain why.
The Standard Model is a theory that classifies elementary particles. Evidence for the theory has been collected since about 1950. However, the term Standard Model has only been used since 1973. Suggest why progress in particle physics is slow.
50 exam-style questions on AQA A Level Physics Particles, covering Constituents of the atom, Stable and unstable nuclei, Particles, antiparticles and photons, Particle interactions, Classification of particles, Quarks and antiquarks, and Applications of conservation laws. Each one has a worked solution and a mark scheme showing where the marks go.