Three Body Calculation of theΔΔDibaryon CandidateD03(2370)

Abstract

The D03 dibaryon is generated dynamically as a resonance pole in a πN ∆ ′ three-body model, where ∆ ′ is a stable ∆ baryon. Using separable interactions dominated by the ∆(1232) isobar for πN and by the D12(2150) isobar for N ∆ ′ , with D12(2150) the N ∆ dibaryon deduced in and constrained by 1 D2 pp scattering, the model reduces to an effective two-body problem for ∆∆ ′ which is solved. The mass and width of D03 are found close to those of the I(J P ) = 0(3 + ) resonance peak observed by WASA@COSY in pion-production pn collisions at 2.37 GeV.

Examination of the nature of the ABC effect

“…This is in accordance with meanwhile numerous theoretical work about this resonance [29][30][31][32][33][34][35][36][37][38][39]. It also is in agreement with the measured branchings of the d * decay into the diverse N N ππ channels [40].…”

“…In addition, investigation of such a decay branch into the N N π system can resolve the question, whether the main decay route is d * (2380) → ∆∆ or d * (2380) → D 12 π as anticipated in Refs. [31,32,59]. Since D 12 has a sizeable decay branch into N N , the route via D 12 will feed also the N N π channel, whereas such a feeding is very unlikely to happen with sizeable intensity in case of an intermediate isoscalar ∆∆ system.…”

Recent Results from WASA-at-COSY

“…This group also is so far the only one, who can reproduce the narrow width of d * (2380) by accounting for hidden color configurations [31]. A Faddeev-type calculation using hadronic interactions succeeded recently to reproduce the d * mass [39,40], too, though the calculated width is somewhat larger than the observed one.…”

Resonances at COSY — the dibaryon issue

“…Recently also a relativistic Faddeev-type calculation based on hadronic interactions have been reported to see this state correctly at the experimental mass [60].…”