The weak interaction, in contrast to the strong and electromagnetic, is the mediator of the decay of the strange quark, purely because the weak interaction is 'allowed' to break conservation of flavour quantum numbers (in this case, strangeness number).

Why is the weak interaction endowed with this ability of not obeying flavour number conservation? Thanks!

  • $\begingroup$ There are two types of flavor violations, within the generation and between generations. The one within the same generation is just a change of the electric charge. How is a change between the up and down quarks different from a change between the electron and neutrino? In both the only thing that changes is the electric charge by 1 carried by the W boson. So why do we even say that the up and down quarks are different flavors while the ekectron and electron-type neutrino are the same flavor? Makes no sense. The true violation here is between generations and it is not explained in the link. $\endgroup$ – safesphere Sep 22 '17 at 1:32