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Xi decay quarks conserved but flavour not conserved

  1. Nov 13, 2012 #1
    Hi

    I have been looking into particle physics and i came across this question but i can not find the answer,

    the quetsion is as follows:

    the xi particle decays into the following
    [itex]\Xi -> \wedge + \Pi^{-}[/itex]
    dds -> sud + [itex]\overline{u}d [/itex]
    the quark numbers are conserved but the flavours are not conserved.

    I cannot understand why the flavours are not conserved. Can anyone help me?
     
  2. jcsd
  3. Nov 13, 2012 #2

    mfb

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    Where does that come from?
    Looks conserved to me.

    The long lifetime (~10-10s) is suspicious.
     
  4. Nov 13, 2012 #3
    It says on it why isnt it conserved and is it decayed by strong or weak forces.
    I would say weak because flavours are not conserved but by looking at it, it seems to be conserved
     
  5. Nov 13, 2012 #4

    mfb

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    Well, it is easy to draw a diagram for the strong interaction.

    The long lifetime indicates that those diagrams are problematic in terms of parity, or cancel each other partially, or something else.

    Edit @Bill_K's post: Oh, that explains everything. And ##\Sigma^-## with dds is too light to decay into ##\Lambda + \pi##
     

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    Last edited: Nov 13, 2012
  6. Nov 13, 2012 #5

    Bill_K

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    The Ξ- (aka cascade particle) is not dds, it's dss. The decay is weak because it does not conserve strangeness.
     
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