We show, from a diabatic analysis of lattice results for string breaking, that mixing of $Q\overline{Q}$ with open-flavor meson-meson configurations may be expressed through a mixing potential which is order $1/m_Q$. A relation between the minimum string breaking energy gap and the string tension comes out naturally. Using this relation, and matching the energy gap for $b\overline{b}$ with lattice QCD data, we study the mixing in the $c\overline{c}$ case without any additional parameter. A $1^{++}$ bound state very close below the $D^0{\overline{D}}^{*0}$ threshold, in perfect correspondence with ${\chi }_{c1}(3872)$, is predicted.

• Received 2 December 2021
• Accepted 4 March 2022

DOI:https://doi.org/10.1103/PhysRevD.105.054028

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Published by the American Physical Society