  The Dalitz-plot of the Decay D0 --> pi+ pi- pi0 measured by the BABAR
Collaboration shows the structure of a final state having quantum numbers IG
JPC = 0- 0--. An isospin analysis of the Daliz-plot finds that the I = 0
contribution is about 96%. This high I = 0 contribution is unexpected because
the weak interaction violates the isospin.
