How to understand the X(2900)?

In this work, the S - and P -wave D ¯ ∗ K ∗ interactions are studied in a coupled-channel formalism to understand the recently observed X 0 ( 2900 ) and X 1 ( 2900 ) at LHCb. The experimental event distributions can be well described, and two states with I ( J P ) = 0 ( 0 + ) and 0 ( 1 - ) are yielded in a unified framework. The masses of the 0 + and 1 - states are consistent with the experimental data, but the width of the 0 + state is larger than that of the 1 - one. The X 1 ( 2900 ) can be interpreted as the P -wave excitation of the ground-state X 0 ( 2900 ) in the hadronic molecular picture. The S - and P -wave multiplets in the D ¯ ∗ K ∗ system have many members, so the present peak in the D - K + invariant mass distributions might contain multi substructures.