# Rho meson decay question

1. Mar 2, 2012

### benjammin

Does anyone know why the $$\rho^0\to\pi^0\gamma$$ decay is suppressed? I've been working on it, and so far I think it can conserve parity, charge conjugation, angular momentum, etc. But the PDG indicates that it basically never happens. Why?

Thanks!

2. Mar 2, 2012

### Hepth

Unless there's something deeper I'm missing, I assume its due to the neutral nature of each meson. At lowest order in chiral perturbation theory there are no tree level diagrams for this decay.

Benjammin, are you from Detroit by any chance? (Don't have to answer publicly)

3. Mar 2, 2012

### fzero

$\Gamma_i/\Gamma \sim 4.5\cdot 10^{-4}$ is far different from "basically never happens." $\rho^0\rightarrow \pi^+\pi^-$ is favored because it can proceed via the strong interaction. $\rho^0\rightarrow \pi^0\gamma$ is primarily EM.