Suggest why the kaon is classified as a boson.

A kaon decays into an antimuon and a neutrino, K⁺ →μ ⁺+v . The Feynman diagram for the decay is shown below.

(i) State the two particles labelled X and Y.

(ii) Explain how it can be deduced that this decay takes place through the weak interaction.

(iii) State the name and sign of the electric charge of the particle labelled A.

the spin number of a boson is an integer value;
the spin of the kaon can be \(\frac{1}{2} + \frac{1}{2} = 1\) or \(\frac{1}{2} - \frac{1}{2} = 0\)

(i) X: anti-strange quark / \(\bar s\);
Y: antimuon / μ⁺;

(ii) the process violates strangeness number conservation;
only the weak interaction allows this violation;

or

the decay of the kaon involves a neutrino;
any decay involving the neutrino must take place by the weak interaction;

(iii) name: W (boson);
sign: positive;