A New Dispersive Analysis of eta --> 3 pi

Abstract

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.

Comments: 9 pages, 4 figures, to be published in the proceedings of 6th International Workshop on Chiral Dynamics, CD09, July 6-10, 2009, Bern, Switzerland