Study of the decays of S -wave D¯*K* hadronic molecules: The scalar X0(2900) and its spin partners X˜J(J=1,2)

Abstract

In this work, we investigate the decays of the fully open-flavor tetraquark state ${X}_{0}(2900)$ which was observed by the LHCb collaboration very recently. By using an effective Lagrangian approach, the partial widths of ${X}_{0}(2900)$ are estimated, where ${X}_{0}(2900)$ is assumed to be an $S$-wave ${\overline{D}}^{*}{K}^{*}$ hadronic molecule with $I=0$. It is found that the estimated results are in agreement with the experimental observations. Moreover, we also predict the decay behaviors of the other unobserved ${\stackrel{\texttildelow{}}{X}}_{J(J=1,2)}$, which are the spin partners of the ${X}_{0}(2900)$ in the $S$-wave ${\overline{D}}^{*}{K}^{*}$ picture. It is pointed out that the ${\stackrel{\texttildelow{}}{X}}_{1}$ state with $I=0$ is a broad state with the width more than 100 MeV, while another ${\stackrel{\texttildelow{}}{X}}_{2}$ state with $I=0$ is a narrow state with the width approaching half of that for the ${X}_{0}(2900)$. In addition, our results also show that the ${\overline{D}}^{*}K$ mode is expected to be the dominant decay mode for both ${\stackrel{\texttildelow{}}{X}}_{1}$ and ${\stackrel{\texttildelow{}}{X}}_{2}$. Searching for those unobserved ${\stackrel{\texttildelow{}}{X}}_{J(J=1,2)}$ in the future experiments might be helpful to understand the nature of ${X}_{0}(2900)$.