Rescattering effects in eta {\to} 3pi decays

Understand

The isospin-breaking decay eta {\to} 3pi is an ideal tool to extract information on light quark mass ratios from experiment.

• For a precise determination, however, a detailed description of the Dalitz plot distribution is necessary.
• In that respect, in particular the slope parameter alpha of the neutral decay channel causes some concern, since the one-loop prediction from chiral perturbation theory misses the experimental value substantially.
• We use the modified non-relativistic effective field-theory, a dedicated framework to analyze final-state interactions beyond one loop including isospin-breaking corrections, to extract charged and neutral Dalitz plot parameters.