$G$-parity violating amplitudes in the $J/\psi \to {\pi }^{+}{\pi }^{-}$ decay

Rinaldo Baldini Ferroli, Alessio Mangoni, Simone Pacetti

The decays of the negative $G$-parity meson $J/\psi$ into even numbers of pions violate $G$-parity. Such decays, as well as other $G$-parity decays into hadrons, can be parametrized i…