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arXiv · 0912.3440

Cusp effects in meson decays

Bastian Kubis
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Abstract

The pion mass difference generates a pronounced cusp in the pi0 pi0 invariant mass distribution of K+ --> pi0 pi0 pi+ decays. As originally pointed out by Cabibbo, an accurate measurement of the cusp may allow one to pin down the S-wave pion-pion scattering lengths to high precision. We present the non-relativistic effective field theory framework that permits to determine the structure of this cusp in a straightforward manner, including the effects of radiative corrections. Applications of the same formalism to other decay channels, in particular eta and eta' decays, are also discussed.

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Bastian Kubis. 2009-12-17. Cusp effects in meson decays. https://doi.org/10.1051/epjconf%2F20100301008

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