Patterns of CP violation from mirror symmetry breaking in the η → π+ π− π0 Dalitz plot

A violation of mirror symmetry in the η → π+ π− π0 Dalitz plot has long been recognized as a signal of C and C P violation. Here we show how the isospin of the underlying C- and CP-violating structures can be reconstructed from their kinematic representation in the Dalitz plot. Our analysis of the most recent experimental data reveals, for the first time, that the C- and CP-violating amplitude with total isospin I = 2 is much more severely suppressed than that with total isospin I = 0 .