New scalar resonance $X_0(2900)$ as a $\overline{D}^{*}K^{*}$ molecule: Mass and width

TL;DR

This paper investigates the scalar resonance $X_0(2900)$ as a hadronic molecule of $ar{D}^*0$ and $K^{*0}$, calculating its mass and width using QCD sum rules, supporting its molecular interpretation.

Contribution

It provides a novel QCD sum rule analysis of $X_0(2900)$ as a $ar{D}^*K^*$ molecule, including mass, coupling, and decay width calculations.

Findings

Mass prediction: $2868 \,\mathrm{MeV}$ with uncertainty

Width prediction: $49.6 \,\mathrm{MeV}$ with uncertainty

Supports molecular interpretation of $X_0(2900)$

Abstract

We explore features of the scalar structure $X_0(2900)$, which is one of the two resonances discovered recently by LHCb in the $D^{-}K^{+}$ invariant mass distribution in the decay $B^{+} \to D^{+}D^{-}K^{+}$. We treat $ X_0(2900)$ as a hadronic molecule composed of the conventional mesons $ \overline{D}^{* 0} $ and $K^{*0}$ and calculate its mass, coupling and width. The mass and coupling of $X_0(2900)$ are determined using the QCD two-point sum rule method by taking into account quark, gluon, and mixing vacuum condensates up to dimension $15$. The decay of this structure to final state $D^{-}K^{+}$ is investigated in the context of the light-cone sum rule approach supported by a soft-meson technique. To this end, we evaluate strong coupling $G$ corresponding to vertex $X_0D^{-}K^{+}$, which allows us to find width of the decay $X_0(2900) \to D^{-}K^{+}$. Obtained predictions for the mass of the hadronic molecule $\overline{D}^{*0 }K^{*0}$ $m=(2868 \pm 198)~\mathrm{MeV} $ and for its width $\Gamma=(49.6 \pm 9.3)~ \mathrm{MeV}$ can be considered as arguments in favor of molecule interpretation of $X_0(2900)$.