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Why do we never observe the decay of this particle?

  1. Feb 27, 2012 #1
    Hey why do we observe the Ʃ(minus) decay into n+e+anti-e-neutrino?But never

    Ʃ+--->n + positron+ ve( electron neutrino)
  2. jcsd
  3. Feb 27, 2012 #2
    First (although the notation is confusing) [itex]Ʃ^{+}[/itex] and [itex]Ʃ^{-}[/itex] are not a particle-antiparticle pair, they are patners in an isospin triplet. So there is no reason that the two decays should be related. [itex]Ʃ^{+}[/itex] is composed of suu and it would two W exchanges (netral vector bosons don't mix flavour), while [itex]Ʃ^{-}[/itex] is composed of sdd which requires only one W exchange.
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