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

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 (D) over bar *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 (X) over tilde (J(J=1,2)), which are the spin partners of the X-0(2900) in the S-wave D<overline> K picture. It is pointed out that the X 1 state with I = 0 is a broad state with the width more than 100 MeV, while another X 2 state with I = 0 is a narrow state with the width approaching half of that for X-0(2900). In addition, our results also show that the (D) over bar *K* mode is expected to be the dominant decay mode for both (X) over tilde (1) and (X) over tilde (2). Searching for those unobserved (X) over tilde (J(J=1,2)) in the future experiments might be helpful to understand the nature of X-0(2900).