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A decay amplitude changing strangeness by two units requires at least two insertions of the low-energy weak interaction in the Standard Model. Each charged-current insertion can remove only one net strange quark in such a process. Both two-W boson tree topologies and loop contributions can occur; a loop is not required for every exclusive final state. At hadronic energies, the extra power of the Fermi constant, with the needed powers of an energy scale to balance units, strongly suppresses a second-order amplitude relative to a first-order one. This is distinct from Cabibbo suppression within a fixed weak order.

The baryon octet contains an isospin triplet ${\Sigma }^{+},{\Sigma }^0,{\Sigma }^{-}$. Each has strangeness $-1$; their valence quark contents are $uus$, $uds$, $dds$.

Strong and electromagnetic interactions conserve net strangeness; a decay changing it requires the weak interaction. A strange baryon decay into a less-strange baryon and a pion is an example. The weak interaction does not impose a parity selection rule, so a final orbital partial wave cannot by itself determine the parent's parity. Qualitative lifetime classes do not provide an exact lifetime without an amplitude calculation or measurement.

A hyperon decay that changes quark flavour while emitting a photon. An example is ${\Xi }^0\to \Lambda \gamma$, which changes strangeness and cannot be purely electromagnetic. Its amplitude can contain short-distance loops and long-distance hadronic contributions. photon attachments to a weak quark-exchange graph must be completed consistently with electromagnetic gauge invariance. A quark topology identifies allowed flavour flow but does not by itself calculate a reliable hadronic rate.

The baryon octet contains the isospin doublet ${\Xi }^0,{\Xi }^{-}$. Each has strangeness $-2$, with valence quark content $uss$, $dss$.