Speaker
Description
Experimentally many exotic charmonium-like mesons have already been discovered, for example, the $Z_c$ mesons. We study the spectrum of such states with isospin 1 focusing on the $\bar cc \bar qq$ channels with $J^{P}=1^{+}$, $C=\pm$. This is the first study of four-quark states with these quantum numbers, where the total momentum is non-zero. The simulations are performed on two $N_{\textrm{f}}=2+1$ CLS ensembles with different volumes and $m_{\pi}\simeq~280\,$MeV. We extract the finite-volume energy levels and determine the scattering amplitude assuming decoupled $D\bar D^*$ scattering close to the threshold using Lüscher's formalism. Additionally, one-channel $J/\psi \pi$ scattering for $C=-$ is considered, and upper bounds are put on the scattering length and $1/(p \cot{\delta})$ in certain energy regions, which constrains the interaction between $J/\psi$ and $\pi$.
| Topical area | Hadronic and Nuclear Spectrum and Interactions |
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