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An important result of the hadron programme at COSY (Jülich, Germany) is the isoscalar resonance with the mass of 2380 MeV and width of about 70 MeV observed by the WASA collaboration in the reactionpn→dπ0π0.

Its closeness to the formation threshold of two Δ(1232) isobars suggests that the observed resonance has a quasi-molecular ΔΔ-structure while its unusually narrow width  indicates a possible dibaryon (six-quark) nature. This observation stimulated calculations using both quark models and πNΔ-dynamics. The ANKE@COSY collaboration observed a resonance with a mass of 2380 MeV in the reaction pd→pdππ  beyond the quasi-elastic kinematics and two isovector resonances in the reaction pp→{pp}sπ0 with the formation of a 1S0-diproton. Theoretical calculations of cross sections for these reactions with allowance for excitation of the Δisobar, N*(1440), D12(2150) were reported. A brief review of the talks on exotic hadron systems at the MESON-2018 conference (Krakow, 7–12 June2018) was also given.

For more detail, see here.