<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>X</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msub><mml:mo stretchy="false">(</mml:mo><mml:mn>2866</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math> as a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>D</mml:mi></mml:mrow><mml:mrow><mml:mo>*</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mover accent="true"><mml:mrow><mml:mi>K</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">¯</mml:mo></mml:mrow></mml:mover></mml:mrow><mml:mrow><mml:mo>*</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math> molecular state

Abstract

Very recently the LHCb Collaboration reported the discovery of two open charm tetraquark states, ${X}_{0}(2866)$ and ${X}_{1}(2904)$. In the present work, we study the ${D}^{(*)}$ and ${\overline{K}}^{(*)}$ interaction in the one-boson exchange model and show that ${X}_{0}(2866)$ can be understood as a ${D}^{*}{\overline{K}}^{*}$ molecule with $I({J}^{P})=0({0}^{+})$, or at least it has a large molecular component. On the other hand, ${X}_{1}(2904)$ can not be interpreted as a molecular state. Inspired by the discovery of ${X}_{0}(2866)$ and the fact that the ${D}^{*}{\overline{K}}^{*}$ interaction is strong enough to generate a bound state, we also discuss the likely existence of other open charm molecules. In the meson-meson sector, two molecules near the mass thresholds of $D{D}^{*}$ and ${D}^{*}{D}^{*}$ with $I({J}^{P})=0({1}^{+})$ are obtained, and using the heavy quark flavor symmetry their $\overline{B}{\overline{B}}^{*}$ and ${\overline{B}}^{*}{\overline{B}}^{*}$ counterparts are also predicted. In the meson-baryon sector, seven open charm molecules with $I=1/2$ near the mass thresholds of ${D}^{(*)}{\mathrm{\ensuremath{\Sigma}}}_{c}^{(*)}$ naturally appear, as dictated by the heavy quark spin symmetry.

Topics & Concepts