New scalar resonance X0(2900) as a (D)over-bar*K* molecule: mass and width

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+ -> D+ D- K+. We treat X-0(2900) as a hadronic molecule composed of the conventional mesons (D) over bar*(0) 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 X0D- K+, which allows us to find width of the decay X-0(2900) -> D- K+. Obtained predictions for the mass of the hadronic molecule (D) over bar*K-0*(0) m = (2868 +/- 198) MeV and for its width Gamma = (49.6 +/- 9.3) MeV can be considered as arguments in favor of molecule interpretation of X-0(2900).

Automated summary

This study explores the features of the scalar structure X-0(2900) and treats it as a hadronic molecule composed of conventional mesons. The mass, coupling, and width of X-0(2900) are calculated using QCD two-point sum rule method. The predictions for the mass and width of the hadronic molecule support the molecule interpretation of X-0(2900).