<Tr> <Td> π ν </Td> <Td> semileptonic </Td> <Td> 7000507000000000000 ♠ 5.07 ± 0.04% </Td> </Tr> <Tr> <Td> π μ ν </Td> <Td> semileptonic </Td> <Td> 7000335300000000000 ♠ 3.353 ± 0.034% </Td> </Tr> <P> Decay modes for the are charge conjugates of the ones above . </P> <P> The discovery of hadrons with the internal quantum number "strangeness" marks the beginning of a most exciting epoch in particle physics that even now, fifty years later, has not yet found its conclusion...by and large experiments have driven the development, and that major discoveries came unexpectedly or even against expectations expressed by theorists .--I.I. Bigi and A.I. Sanda, CP violation, (ISBN 0 - 521 - 44349 - 0) </P>

The positive kaon can also decay to form a