Charmonium-like resonances in coupled $D \bar D$-$D_s \bar D_s$ scattering

TL;DR

This study uses lattice QCD to identify and analyze charmonium-like resonances and bound states in coupled $Dar D$ and $D_sar D_s$ scattering, revealing new states and clarifying their relation to observed particles.

Contribution

The paper provides the first lattice QCD evidence for multiple charmonium-like states in coupled scattering channels, including a previously unobserved $Dar D$ bound state and clarifies their connection to experimental resonances.

Findings

Identification of three $J^{PC}=0^{++}$ states, including a new $Dar D$ bound state.

Observation of resonances related to known charmonia such as $ ext{X}(3915)$.

Analysis of scattering channels reveals states with $J^{PC}=1^{--}, 2^{++}, 3^{--}$.

Abstract

Charmonium-like resonances and bound states with isospin zero and $J^{PC}=0^{++},~1^{--},~2^{++},~3^{--}$ are extracted on the lattice. Coupled $D\bar D$ and $D_s\bar D_s$ scattering suggests three charmonium-like states with $J^{PC}=0^{++}$ in addition to $\chi_{c0}(1P)$: a so far unobserved $D\bar D$ bound state just below threshold, a conventional resonance likely related to $\chi_{c0}(3860)/\chi_{c0}(2P)$ and a narrow resonance just below the $D_s\bar D_s$ threshold with a large coupling to $D_s\bar D_s$ likely related to $X(3915)/\chi_{c0}(3930)$. One-channel $D\bar D$ scattering renders resonances and bound states with $J^{PC}= 1^{--},~2^{++},~3^{--}$ related to the observed conventional charmonia. Lattice QCD ensembles from the CLS consortium with $m_{\pi}\simeq 280$ MeV are utilized.