# [particle physics] Decay of baryon

1. May 28, 2012

### nonequilibrium

1. The problem statement, all variables and given/known data
Are the following reactions possible? If yes, explain why and how the reaction occurs. If no, explain why.

...

$\Delta^+ \to p^+ + \pi^0$"

2. Relevant equations
NA

3. The attempt at a solution
First of all, it wouldn't break any conservation law, hence it is possible (or is this reasoning faulty? In other words is there an example of something not breaking any conservation law, even kinematically, yet not happening since it has no possible Feynman diagram?)

Now, although I'm sure it's possible, I'm not sure what to answer on "how the reaction occurs": am I right in thinking that it is possible through all three interactions? (strong, electromagnetic, weak)

I can think of two sensible things to answer: either list all possible reactions, or list the dominant one (always the strong force when possible via that interaction?). Which of the two is most sensible? And to specifically describe that strong interaction, I would draw the following beautiful picture

Is this correct? And is it also of lowest order, or am I overlooking something simpler? (am I right in thinking that I can NOT leave out the second gluon, cause otherwise that branch on the right hand side would be detached from the other branch, which is not allowed (?))

EDIT: on second thought, the first gluon seems superfluous?

#### Attached Files:

• ###### decay.gif
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2. May 29, 2012

### fzero

Yes, it is. The single gluon diagram is dominant.