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arXiv · 2009.05616

Possible manifestation of the 2p pionium in particle physics processes

Peter Lichard
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Abstract

We suggest a few particle physics processes in which excited 2p pionium $\mathrm{A}^\prime_{2\pi}$ may be observed. They include the $e^+e^-\to\pi^+\pi^-$ annihilation, the $V^0\to\pi^0\ell^+\ell^-$ and $K^\pm\to\pi^\pm\ell^+\ell^-$ ($\ell=e,\mu$) decays, and the photoproduction of two neutral pions from nucleons. We analyze available experimental data and find that they, in some cases, indicate the presence of 2p pionium, but do not provide definite proof.

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Peter Lichard. 2020-09-11. Possible manifestation of the 2p pionium in particle physics processes. https://doi.org/10.1103/physrevd.102.073004

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