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arXiv · 1010.3946

Rescattering effects in eta {\to} 3pi decays

Sebastian P. Schneider·Bastian Kubis·Christoph Ditsche
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Abstract

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. Matching to chiral perturbation theory at next-to-leading order, we find alpha = -0.025 +- 0.005, in marginal agreement with experimental findings. We derive a relation between charged and neutral decay parameters that points towards a significant tension between the most recent KLOE measurements of these observables.

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Sebastian P. Schneider, Bastian Kubis, Christoph Ditsche. 2011-02-16. Rescattering effects in eta {\to} 3pi decays. https://doi.org/10.1007/jhep02(2011)028

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