Decoding Two-Particle States in QCD with Spatial Wavefunctions

Abstract

A systematic framework for constructing optimized interpolating operators strongly coupled to QCD two-particle states is developed, which is achieved by incorporating inter-hadron spatial wavefunctions. To efficiently implement these operators in lattice QCD, a novel quark smearing technique utilizing noise vectors is proposed. Applied to the $\hat{I}{\text{c◯}}_{ccc}\hat{I}{\text{c◯}}_{ccc}$ system, these optimized operators prove superior to combinations of limited plane-wave operators, enabling the resolution of distinct eigenstates separated by only $\sim 5$ MeV near the threshold $2m_{\hat{I}{\text{c◯}}_{ccc}}\simeq 9700$ MeV. This exceptional resolving power opens new possibilities for studies of a wide range of hadronic systems in QCD.

6 pages; Including comparisons with plane-wave operators to match with the published version