Decay width of the pentaquark state ${\mathrm{\Theta }}^{+}(1540)$ with QCD sum rules

In this article, we take the point of view that the pentaquark state ${\mathrm{\Theta }}^{+}(1540)$ has negative parity, and choose the diquark-triquark type interpolating current to calculate the strong coupling constant $g_{\mathrm{\Theta }NK}$ in the QCD sum rule approach. Our numerical results indicate the values of the strong coupling constant $g_{\mathrm{\Theta }NK}$ are very small, $|g_{\Theta NK}|=0.175\pm0.084$,andthewidth$\Gamma_\Theta <4MeV$, which can explain the narrow width $\mathrm{\Gamma }\le 10MeV$ naturally.