Why does Δ+ decay to n + π+ via the weak force?

[12x4]

Homework Statement

:[/B]

For the decay of the ∆⁺ → n + π⁺, sketch an appropriate quark-level Feynman diagram.

State which interaction is responsible for this decay.

3. The Attempt at a Solution
This is more of a question to see if I'm doing it right more than anything. The first Feynman diagram is one where the strong force is responsible for the decay. The second one is one where the weak force is responsible, I'm not to sure if I'm allowed to do it both ways but if am how can I tell which one to use?

 

[Orodruin]

Both are allowed, but which do you think dominates?

 

[12x4]

strong force? Its a much stronger reaction.

 

[Orodruin]

Yes, and so we call it a strong decay.