Scalar and Tensor Charmonium Resonances from lattice QCD

by David Wilson (University of Cambridge)

Tuesday 22 Oct 2024, 16:00 → 18:00 Europe/Zurich

4/2-037 - TH meeting room (CERN)

Scattering amplitudes with scalar and tensor charmonium resonances are computed using lattice QCD. Working at $m_{\pi }\approx 391$ MeV, more than 200 finite-volume energy levels are computed and these are used in extensions of the Lüscher formalism to determine infinite volume scattering amplitudes. Working in the approximation where charm-annihilation is forbidden, the ground state ${\chi }_{c0}(1P)$ and ${\chi }_{c2}(1P)$ states are stable. Below 4000 MeV we find a single ${\chi }_{c0}$ and a single ${\chi }_{c2}$ resonance, both strongly-coupled to several decay channels consisting of pairs of open-charm mesons. Both resonances are found on the closest unphysical sheet just below $4000$ MeV with widths of $\approx$ 60 MeV. The largest couplings are to the closed $D^{\ast }{\overline{D}}^{\ast }$ channels in $S$-wave, but several open-charm channels are also found to be large and significant in both cases. All closed-charm channels are found to be approximately decoupled. No additional states are found beyond what would be expected from quark-model-like $c\overline{c}$ excitations.

david_wilson_cern_lattice.pdf