# Xi decay quarks conserved but flavour not conserved

by Howlin
Tags: conserved, decay, flavour, quarks
 P: 45 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 $\Xi -> \wedge + \Pi^{-}$ dds -> sud + $\overline{u}d$ the quark numbers are conserved but the flavours are not conserved. I cannot understand why the flavours are not conserved. Can anyone help me?
Mentor
P: 12,028
 the flavours are not conserved.
Where does that come from?
Looks conserved to me.

The long lifetime (~10-10s) is suspicious.
 P: 45 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
 Mentor P: 12,028 Xi decay quarks conserved but flavour not conserved 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## Attached Thumbnails
 Sci Advisor Thanks P: 4,160 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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