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arXiv · hep-ph/9911260

Spectrum and Decays of Hadronic Atoms

J. Gasser·V. E. Lyubovitskij·A. Rusetsky
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Abstract

Using non relativistic effective Lagrangian techniques, we analyze the hadronic decay of the pi+pi- atom and the strong energy-level shift of pionic hydrogen in the ground state. We derive general formulae for the width and level shift, valid at next-to-leading order in isospin breaking. The result is expressed in terms of hadronic threshold amplitudes that include isospin-breaking effects. In order to extract isospin symmetric scattering lengths from the data, we invoke chiral perturbation theory, that allows one to relate the scattering lengths to the threshold amplitudes.

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J. Gasser, V. E. Lyubovitskij, A. Rusetsky. 1999-11-05. Spectrum and Decays of Hadronic Atoms. https://arxiv.org/abs/hep-ph/9911260

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