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## Main Question or Discussion Point

Decay \eta\to\pi^0\gamma is forbidden by C parity. But why this decay is also forbidden by statistics (J)?

pi^0 spin is 0

photon spin is 1

But there are can be different situations with full orbital angular momentum of pi^0\gamma.

J=L+S and must be 0. Look like L is 0. But why? Why we can't have L=1 in this case? (unlike in \rho\to\pi^0\gamma decay)

pi^0 spin is 0

photon spin is 1

But there are can be different situations with full orbital angular momentum of pi^0\gamma.

J=L+S and must be 0. Look like L is 0. But why? Why we can't have L=1 in this case? (unlike in \rho\to\pi^0\gamma decay)

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