Speakers
Description
Hybrid quarkonia may provide firm candidates to explain some of the so-called XYZ mesons. We investigate charmonium and bottomonium hybrids using the Born-Oppenheimer Effective Field Theory and incorporating the latest lattice QCD results for hybrid static potentials.
In this talk, we discuss hybrid-to-quarkonium semi-inclusive decay widths for both spin-conserved and spin-flip channels. A key focus of the presentation is a comprehensive error analysis: we quantify the uncertainties arising from higher-order terms in the multipole expansion, relativistic effects, and the critical mismatch between the weak- and strong-coupling regimes, which dominates the error budget.
Finally, we confront our theoretical predictions with the latest PDG data. By comparing masses and reliable transition rates, we discuss the assignment of several isospin-zero XYZ resonances. In particular, we highlight specific cases such as the $\psi(4360)$ and $\psi(4415)$, which emerge as consistent hybrid candidates, and $\Upsilon(10860)$, whose purely hybrid interpretation is disfavored by our decay width calculations.