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arXiv · 2603.08846

The ultrafine splitting of heavy quarkonium with next-to-next-to-next-to-next-to-leading-order accuracy

Jose M. Escario·Andreas Maier·Clara Peset·Antonio Pineda
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Abstract

We compute the hyperfine splitting of P-wave heavy quarkonium states with next-to-next-to-next-to-next-to-leading-order accuracy. The resummation of logarithms with next-to-next-to-next-to-next-to-leading-logarithmic accuracy is also addressed. A phenomenological analysis of these results is performed for bottomonium, charmonium and the $B_c$ system. We also apply these results to positronium, muonium, hydrogen and muonic hydrogen.

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Jose M. Escario, Andreas Maier, Clara Peset, Antonio Pineda. 2026-03-09. The ultrafine splitting of heavy quarkonium with next-to-next-to-next-to-next-to-leading-order accuracy. https://arxiv.org/abs/2603.08846

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