A New Dispersive Analysis of eta --> 3 pi

Understand

We present a new dispersive analysis of the isospin breaking decay eta --> 3 pi.

• The resulting representation of the decay amplitude allows us to determine the quark mass double ratio Q and we find as a preliminary result Q = 22.3 +/- 0.4.
• Finally, we discuss a number of improvements that we intend to implement in the future.