G-parity
(重定向自G Parity)
In theoretical physics, G-parity is a multiplicative quantum number that results from the generalization of C-parity to multiplets of particles.
C-parity applies only to neutral systems; in the pion triplet, only π has C-parity. On the other hand, strong interaction does not see electrical charge, so it cannot distinguish amongst π, π and π. We can generalize the C-parity so it applies to all charge states of a given multiplet: