“School of Particles And Accelerator”
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Paper IPM / Particles And Accelerator / 17036  


Abstract:  
We investigate properties of the groundstate and first radially excited fourquark mesons $X_0$ and $X_0^{\prime}$ with a diquarkantidiquark structure $[ud][\overline{c}\overline{s}]$ and spinparities $J^{\mathrm{P}}=0^{+}$. Our aim is to reveal whether or not one of these states can be identified with the resonance $X_0(2900)$, recently discovered by the LHCb collaboration. We model $X_0$ and $X_0^{\prime}$ as tetraquarks composed of either axialvector or scalar diquark and antidiquark pairs. Their spectroscopic parameters are computed by employing the QCD twopoint sum rule method and including into analysis vacuum condensates up to dimension $15$. For an axialaxial structure of $X_0^{(\prime)}$, we find partial
widths of the decays $X_0^{(\prime)} \to D^{}K^{+}$ and $X_0^{(\prime)} \to D^{0}K^{0}$, and estimate full widths of the states $X_0^{(\prime)}$. To this end, we calculate the strong couplings at the vertices $X_0^{(\prime)}DK $ in the framework of the lightcone sum rule method. We
use also technical approaches of the softmeson approximation necessary to analyze tetraquarkmesonmeson vertices. Obtained results $m=(2545 \pm 160)~
\mathrm{MeV}$ and $m^{\prime}=(3320 \pm 120)~\mathrm{MeV}$ [$m_{\mathrm{S}}=(2663 \pm 110)~\mathrm{MeV}$ and $m_{\mathrm{S}}^{\prime}=(3325 \pm 85)~\mathrm{MeV}$ for a scalarscalar current] for the masses of the particles $
X_0$ and $X_0^{\prime}$, as well as estimates for their full widths $\Gamma_{0}=(140 \pm 29)~\mathrm{MeV}$ and $\Gamma_{0}^{\prime}=(110 \pm 25)~\mathrm{MeV}$ allow us to interpret none of them as the resonance $X_0(2900)$
. At the same time, these predictions provide important information about groundstate and radially excited diquarkantidiquark structures $X_0$ and $X_0^{\prime}$, which should be objects of future experimental and theoretical studies.
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