LAUSR

A novel framework is proposed to extract near-threshold resonant states from finite-volume energy levels of lattice QCD and is applied to elucidate structures of the positive parity D_{s}. The quark model, the quark-pair-creation mechanism and D^{(*)}K interaction are incorporated into the Hamiltonian effective field theory. The bare 1^{+} cs[over ¯] states are almost purely given by the states with heavy-quark spin bases. The physical D_{s0}^{*}(2317) and D_{s1}^{*}(2460) are the mixtures of bare cs[over ¯] core and D^{(*)}K component, while the D_{s1}^{*}(2536) and D_{s2}^{*}(2573) are almost dominated by bare cs[over ¯]. Furthermore, our model reproduces the clear level crossing of the D_{s1}^{*}(2536) with the scattering state at a finite volume.