Study of the decays of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>S</mml:mi></mml:math>-wave <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mover accent="true"><mml:mi>D</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover><mml:mo>*</mml:mo></mml:msup><mml:msup><mml:mi>K</mml:mi><mml:mo>*</mml:mo></mml:msup></mml:math> hadronic molecules: The scalar <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>X</mml:mi><mml:mn>0</mml:mn></mml:msub><mml:mo stretchy="false">(</mml:mo><mml:mn>2900</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:math> and its spin partners <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mover accent="true"><mml:mrow><mml:mi>X</mml:mi></mml:mrow><mml:mrow><mml:mo accent="true" stretchy="false">˜</mml:mo></mml:mrow></mml:mover></mml:mrow><mml:mrow><mml:mi>J</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mi>J</mml:mi><mml:mo>=</mml:mo><mml:mn>1</mml:mn><mml:mo>,</mml:mo><mml:mn>2</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:msub></mml:mrow></mml:math>

Abstract

In this work, we investigate the decays of the fully open-flavor tetraquark state ${X}_{0}(2900)$ which was observed by the LHCb collaboration very recently. By using an effective Lagrangian approach, the partial widths of ${X}_{0}(2900)$ are estimated, where ${X}_{0}(2900)$ is assumed to be an $S$-wave ${\overline{D}}^{*}{K}^{*}$ hadronic molecule with $I=0$. It is found that the estimated results are in agreement with the experimental observations. Moreover, we also predict the decay behaviors of the other unobserved ${\stackrel{\texttildelow{}}{X}}_{J(J=1,2)}$, which are the spin partners of the ${X}_{0}(2900)$ in the $S$-wave ${\overline{D}}^{*}{K}^{*}$ picture. It is pointed out that the ${\stackrel{\texttildelow{}}{X}}_{1}$ state with $I=0$ is a broad state with the width more than 100 MeV, while another ${\stackrel{\texttildelow{}}{X}}_{2}$ state with $I=0$ is a narrow state with the width approaching half of that for the ${X}_{0}(2900)$. In addition, our results also show that the ${\overline{D}}^{*}K$ mode is expected to be the dominant decay mode for both ${\stackrel{\texttildelow{}}{X}}_{1}$ and ${\stackrel{\texttildelow{}}{X}}_{2}$. Searching for those unobserved ${\stackrel{\texttildelow{}}{X}}_{J(J=1,2)}$ in the future experiments might be helpful to understand the nature of ${X}_{0}(2900)$.

Topics & Concepts