X(2900) in a chiral quark model

TL;DR

This study investigates the possible internal structures of the X(2900) tetraquark states using a chiral quark model, finding potential P-wave excited states as candidates and suggesting negative parity for X(2900).

Contribution

It is the first comprehensive analysis of X(2900) structures considering molecular and diquark configurations within a chiral quark model, employing the Gaussian expansion and stabilization methods.

Findings

No candidates found in S-wave systems below threshold.

Two P-wave excited states identified as potential X(2900) candidates.

X(2900) possibly has negative parity, with some states above threshold.

Abstract

Recently, the LHCb Collaboration reported their observation of the first two fully open-flavor tetraquark states named $X_0(2900)$ and $X_1(2900)$ with unknown parity. Inspired by the report, we consider all of possible four-quark candidates of $X(2900)$ including molecular structure and diquark structure in a chiral quark model with the help of Gaussian expansion method. Two different structures coupling is also considered. To identify the genuine resonances, real-scaling method (stabilization method) was employed. The results show that no candidate of $X(2900)$ is founded in $00^+$ and $01^+$ $cs\bar{q}\bar{q}$ system below the threshold of $D^*\bar{K}^*$, while there are two states in the $P$-wave excited $cs\bar{q}\bar{q}$ system, $D_1\bar{K}$ and $D_J\bar{K}$, which could be candidates of $X(2900)$. In this way, we assign negative parity to $X_1(2900)$, and $X_0(2900)$ maybe a resonance state above the threshold of $D^*\bar{K}^*$, more calculation is needed.