Very recently the LHCb Collaboration reported their observation of the first two fully open-flavor tetraquark states, the $X_0(2900)$ of $J^P = 0^+$ and the $X_1(2900)$ of $J^P = 1^-$. We study their possible interpretations using the method of QCD sum rules, paying special attention to an interesting feature of this experiment that the higher resonance $X_1(2900)$ has a width significantly larger than the lower one $X_0(2900)$. Our results suggest that the $X_0(2900)$ can be interpreted as the $S$-wave $D^{*-}K^{*+}$ molecule state of $J^P = 0^+$, and the $X_1(2900)$ can be interpreted as the $P$-wave $\bar c \bar s u d$ compact tetraquark state of $J^P = 1^-$. Mass predictions of their bottom partners are also given.

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X 0(2900) 和 X 1(2900)：强子分子或致密四夸克

最近 LHCb Collaboration 报告了他们对前两个完全开放风味的四夸克状态的观察，$J^P = 0^+$ 的 $X_0(2900)$ 和 $J^P = 的 $X_1(2900)$ 1^-$。我们使用 QCD 求和规则的方法研究它们的可能解释，特别注意本实验的一个有趣特征，即较高共振 $X_1(2900)$ 的宽度明显大于较低共振 $X_0(2900)$。我们的结果表明，$X_0(2900)$ 可以解释为 $J^P = 0^+$ 的 $S$-wave $D^{*-}K^{*+}$ 分子态，并且$X_1(2900)$ 可以解释为$J^P = 1^-$ 的$P$-wave $\bar c \bar sud$ 紧致四夸克态。还给出了他们底层伙伴的大量预测。