DK/Dπ scattering and an exotic virtual bound state at the SU(3) flavour symmetric point from lattice QCD

A bstract Elastic S -wave scattering of a charm meson with a light pseudoscalar meson in J P = 0 + is investigated in the flavour 3 3 ¯, 6 and 15 15 ¯ sectors at the SU (3) f flavour point using lattice QCD, working on three volumes with m π ≈ 700 MeV. Large bases of interpolating operators are employed to extract finite-volume spectra, which are subsequently used with the Lüscher method to provide constraints on infinite-volume scattering amplitudes. Examining the singularities of the amplitudes, the S -wave amplitude in the flavour 3 3 ¯ sector is found to contain a deeply bound state, strongly coupled to elastic threshold, corresponding to the JP=0^+\ Dₒ₀^ (2317) J P = 0 + D s 0 ∗ 2317. In the exotic flavour 6 sector a virtual bound state is found at s₏₎₋₄ s pole = 2510 – 2610 MeV, roughly 40 – 140 MeV below threshold, whereas the 15 15 ¯ channel shows weak repulsion.