Heavy quark spin symmetry breaking in near-threshold $J^{PC}=1^{--}$ quarkonium-like resonances

TL;DR

The paper investigates how mixing between near-threshold quarkonium-like resonances and heavy meson-antimeson pairs enhances heavy quark spin symmetry breaking, affecting the internal spin structure of bottomonium and charmonium states.

Contribution

It provides a detailed analysis of the mixing effects and proposes experimental processes to study the internal spin structure of these resonances.

Findings

Heavy meson-antimeson pair mixing enhances spin symmetry breaking.

Decomposition of P-wave states reveals specific spin structures.

Proposed experimental processes for studying mixing effects.

Abstract

A mixing of near-threshold quarkonium-like resonances with heavy meson-antimeson pairs results in an enhancement of heavy quark spin symmetry breaking, since the meson pairs are not eigenstates of the heavy quark spin. The decomposition of $P$-wave states of meson pairs in terms of the heavy-quark-pair spin states is considered in the channel with $J^{PC}=1^{--}$, which is directly produced in $e^+e^-$ annihilation. Specific processes are suggested for experimental study of the effects of the mixing with heavy meson pairs and of the internal spin structure of bottomonium and charmonium resonances.