# Homework Help: Forces (Particle Physics)

1. Mar 29, 2010

### latentcorpse

justify which interactions is involved in each of the following:

$\pi^0 \rightarrow \gamma \gamma$
$\pi^+ \rightarrow \mu^+ \nu_\mu$
$\pi^- p \rightarrow \triangle (1232) \rightarrow \pi^0 n$
$K^0 \rightarrow \pi^+ \pi^-$
ok the first one i ruled out strong force since particles on right dont have colour charge. i ruled out weak netural currecnt (Z boson) interaction since fermion flavour isn't conserved. so its between weak charged current ( $W^{\pm}$ boson) or electromagnetic). i think it's probably W boson since photons don't have charge so you can't have a vertex on the Feynman diagram with three photons meeting. is this right?

for the second one, i ruled out strong force and Z boson for same reasons as above. this time, seeing as they are charged, i don't know how to decide between W boson or electromagnetic? any ideas?

i have no clue for the third one since i don't know what $\triangle (1232)$ is.

the fourth one im not sure about either but i have the feeling its a weak interaction. posisbly a W boson since the fermion flavour does change. but im not sure whether its W+ or W- or how to rule out the strong and electromagnetic interactions.

thanks.

Last edited: Mar 30, 2010
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