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Pionium lifetime corrections

H. Sazdjian
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Abstract

Pionium lifetime corrections are evaluated in the frameworks of constrained Bethe-Salpeter equation and chiral perturbation theory. Corrections of order $O(α)$ are calculated with respect to the conventional lowest-order formula, in which the strong interaction amplitude has been calculated to two-loop order with charged pion masses. The total correction is found to be of the order of $(6.1\pm 2.0)%$.

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H. Sazdjian. 1998-09-17. Pionium lifetime corrections. https://arxiv.org/abs/hep-ph/9809425

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