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 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).

Automated summary

In this study, the decays of the observed fully open-flavor tetraquark state X-0(2900) were investigated using an effective Lagrangian approach. The estimated partial widths of X-0(2900) aligned with experimental observations, and predictions were made for the decay behaviors of unobserved states. The results suggest that future experiments searching for these unobserved states may contribute to understanding the nature of X-0(2900).