How to understand the X(2900)?

Abstract

Abstract In this work, the S- and P-wave $$\bar{D}^*K^*$$ D ¯ ∗ K ∗ interactions are studied in a coupled-channel formalism to understand the recently observed $$X_0(2900)$$ X 0 ( 2900 ) and $$X_1(2900)$$ X 1 ( 2900 ) at LHCb. The experimental event distributions can be well described, and two states with $$I(J^P)=0(0^+)$$ I ( J P ) = 0 ( 0 + ) and $$0(1^-)$$ 0 ( 1 - ) are yielded in a unified framework. The masses of the $$0^+$$ 0 + and $$1^-$$ 1 - states are consistent with the experimental data, but the width of the $$0^+$$ 0 + state is larger than that of the $$1^-$$ 1 - one. The $$X_1(2900)$$ X 1 ( 2900 ) can be interpreted as the P-wave excitation of the ground-state $$X_0(2900)$$ X 0 ( 2900 ) in the hadronic molecular picture. The S- and P-wave multiplets in the $$\bar{D}^*K^*$$ D ¯ ∗ K ∗ system have many members, so the present peak in the $$D^-K^+$$ D - K + invariant mass distributions might contain multi substructures.