QCD sum rule approach to the new mesons and the $g_{D_{sJ}DK}$ coupling   constant
  We use diquark-antidiquark currents to investigate the masses and partial decay widths of the recently observed mesons $D_{sJ}^{+}(2317)$, $D_0^{*0}(2308)$ and X(3872), considered as four-quark states, in a QCD sum rule approach. In particular we investigate the coupling constant $g_{D_{sJ}DK}$. We found that the $g_{D_{sJ}DK}$ obtained in this four-quark scenario is smaller than the coupling constant obtained when $D_{sJ}^{+}(2317)$ is considered as a conventional $c\bar{s}$ state. 
Marina Nielsen