Feynman diagram for sigma+ -> n + pi+

[makehhh]

Homework Statement

Hello, I am trying to draw a Feynman Diagram at quark level for the decay sigma+ -> neutron + pi+.

Homework Equations

sigma+ -> neutron + pi+
uus -> udd + udbar

The Attempt at a Solution

Well, the attachment is what I came up with. I have no idea if it's right to be honest, I can't see anything wrong with it, but I have no idea how to be methodical about these kinds of drawings, and haven't found any particle physics texts to be much help.

Thanks for your help!

 

[nicksauce]

Well I can't see your diagram yet, but I think the diagram requires both a W- boson and a Z boson in it.

 

[kaksmet]

At least a W- and then a Z or a gamma.

 

[nicksauce]

So I think your diagram looks OK, but maybe someone else would like to confirm it.

 

[nicksauce]

My alternative was:

 

[makehhh]

Ah, yes that looks good, thanks for your help guys, much appreciated.