91Ó°ÊÓ

Quarks are divided into six flavors: up, down, charm, weird, top, and bottom. The masses of up and down quarks are the smallest of all quarks.

Strange quark s can change flavor by decay path

\[s \to u + {W^ - }\]

The up quark is u₁while the weak force boson is W^-degenerates into W^- very soon.

\[{W^ - } \to {e^ - } + {\nu _e}\]

This isn't the only way to degradation, but it's the most likely. The decay of a negative kaon \[{{\rm{K}}^{\rm{ - }}}{\rm{ = s\bar u}}\]into a neutral pion \[{{\rm{\pi }}^{\rm{0}}}{\rm{ = u\bar u}}\] (or \[{\rm{d\bar d}}\], although this isn't significant for our case) is an example of this decay (because quarks are never isolated due to quark confinement). After then, the degradation begins.

\[{K^ - } \to {\pi ^0} + {\nu _e} + {e^ - }\]

or written in quarks, and in "steps"

\[\overbrace {s(\bar u)}^K \to \overbrace {u(\bar u)}^{{\pi ^0}} + {W^ - } \to u(\bar u) + {\nu _e} + {e^ - }\]Because certain quarks do not participate in the reaction, they are placed in parenthesis.