LAUSR

Abstract We study features of the resonances X ( 2100 ) and X ( 2239 ) by treating them as the axial-vector and vector tetraquarks with the quark content s s s ‾ s ‾ , respectively. The spectroscopic parameters of these exotic mesons are calculated in the framework of the QCD two-point sum rule method. Obtained prediction for the mass m = ( 2067 ± 84 ) MeV of the axial-vector state is in excellent agreement with the mass of the structure X ( 2100 ) recently observed by the BESIII Collaboration in the decay J / ψ → ϕ η η ′ as the resonance in the ϕ η ′ mass spectrum. We also explore the decays X ( 2100 ) → ϕ η ′ and X ( 2100 ) → ϕ η using QCD light-cone sum rule approach and technical methods of the soft-meson approximation. The width of the axial-vector tetraquark, Γ = ( 130.2 ± 30.1 ) MeV , saturated by these two processes is comparable with the measured full width of the resonance X ( 2100 ) . Our prediction for the vector s s s ‾ s ‾ tetraquark's mass m ˜ = ( 2283 ± 114 ) MeV is consistent with the experimental result ( 2239.2 ± 7.1 ± 11.3 ) MeV of the BESIII Collaboration for the mass of the resonance X ( 2239 ) .