Systematic studies of DDKK and D D ¯ K K ¯ four-hadron molecules

Assuming that Ds0∗(2317) is a DK molecular state with a binding energy of 45 MeV, we investigate the existence of four-hadron molecules, DDKK and DD¯KK̄, with the Gaussian expansion method. Their binding energies are 138-155 MeV and 123-163 MeV below the mass thresholds of DDKK and DD¯KK̄. The DD¯KK̄ state has a decay width of 74-107 MeV due to the complex KK̄ interaction. Further theoretical studies of and experimental searches for such four-hadron molecules can help deepen the understanding of the nonperturbative strong interaction in a nontrivial way.