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^0π−+p→K0+Λ0
Λ0\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^0π−+p→Kˉ0+Λ0
State 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}^+ + \gammaη0→e−+e++γ
Compare 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.