From CELSIUS to COSY: on the observation of a dibaryon resonance

الأصل · EN

Using the high-quality beam of storage rings in combination with a pellet target and the hermetic WASA detector covering practically the full solid angle the two-pion production in nucleon-nucleon collisions has been systematically studied by exclusive and kinematically complete measurements -- first at CELSIUS and subsequently at COSY. These measurements resulted in a detailed understanding of the two-pion production mechanism by t-channel meson exchange. The investigation of the ABC effect in double-pionic fusion reactions lead the trace to the observation of a narrow dibaryon resonance with I(Jᵖ) = 0(3+) about 80 MeV below the nominal mass of the conventional ΔΔ system. New neutron-proton scattering data, taken with polarized beam at COSY, produce a pole in the coupled ³D₃ - ³G₃ partial waves at (2380±10 - i 40±5) MeV establishing thus the first observation of a genuine s-channel dibaryon resonance.