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arXiv · 2303.17533

Heavy-Quark spin symmetry breaking in the Born-Oppenheimer approximation

R. Bruschini
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Abstract

Heavy-quark spin symmetry is explicitly broken by the mass splitting between a heavy-light pseudoscalar meson and its vector partner. This fact plays a pivotal role in the physics of states whose mass lies close to the threshold of an open-flavor meson pair, like $X(3872)$. We show that this source of heavy-quark spin symmetry breaking can be systematically included within the diabatic representation of the Born-Oppenheimer approximation. We verify that including all the appropriate coupled channels guarantees conservation of total angular momentum, parity, and charge-conjugation parity. This marks a fundamental step towards a unified, first-principles study of quarkonia and meson molecules with hidden flavor.

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R. Bruschini. 2023-03-30. Heavy-Quark spin symmetry breaking in the Born-Oppenheimer approximation. https://doi.org/10.1007/jhep08(2023)219

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