Abstract
Elastic scattering amplitudes for I = 0 DK and I = 0, 1 $$ D\overline{K} $$
D
K
¯
are computed in S, P and D partial waves using lattice QCD with light-quark masses corresponding to mπ = 239 MeV and mπ = 391 MeV. The S-waves contain interesting features including a near-threshold JP = 0+ bound state in I = 0 DK, corresponding to the $$ {D}_{s0}^{\ast } $$
D
s
0
∗
(2317), with an effect that is clearly visible above threshold, and suggestions of a 0+ virtual bound state in I = 0 $$ D\overline{K} $$
D
K
¯
. The S-wave I = 1 $$ D\overline{K} $$
D
K
¯
amplitude is found to be weakly repulsive. The computed finite-volume spectra also contain a deeply-bound D* vector resonance, but negligibly small P -wave DK interactions are observed in the energy region considered; the P and D-wave $$ D\overline{K} $$
D
K
¯
amplitudes are also small. There is some evidence of 1+ and 2+ resonances in I = 0 DK at higher energies.
Challenges for a QCD axion at the 10 MeV scale
