Existence of Dibaryon Resonances inI=1,D21

Abstract

Recent, precise analyses of p-p and n~p scattering data up to 800 MeV by Arndt et at. have provided the strongest evidence to date for the existence of dibaryon states in the 7 = 1, D 2 and 3 F 2 nucleon-nucleon channels. Model fits to their new phases reveal poles located near the "NA" threshold (2.15 -0.05i GeV). Because of their strong coupling to this channel, these dibaryon resonances are highly inelastic.

Examination of the nature of the ABC effect

“…Refs. [61][62][63][64][65][66][67][68][69][70][71][72]. Since in this route D 12 and the associated pion have to be in relative p-wave, in order to fulfill the angular momentum requirements of D 03 , this decay route is practically indistinguishable from the route D 03 → ∆∆ → dππ, i.e.…”

Encounters with dibaryons - have they finally become true?

“…The possible existence of this resonance was confirmed in the sixties by Dick Arndt [28] analyzing pp scattering data. Later-on, in the eighties and nineties, the SAID data analysis group could demonstrate [29][30][31][32] by partial wave anaylses based on high-quality data for pp → pp, πd → πd and πd → pp that the 1 D 2 partial wave exhibits a pronounced looping in the Argand diagram -in favor of a genuine s-channel resonance. However, since the mass of the resonance is close to the NΔ threshold and since in addition the width of the resonance is compatible with that of the Δ, it has been argued that the observed features represent a NΔ threshold phenomenon rather than a s-channel resonance and the observed looping in the Argand plot is just a reflection of the usual Δ excitation.…”

Analysis of the Dibaryon Resonances with JP=2+ and 3- by a Three-Channel (pp, N , d) K-Matrix Method

“…1) and 2). *) The K-matrix elememts are parametrized as the polynomials in the squared cms energy s, (3) Preliminary analysis suggested that we need at least M = 2 to fit the input amplitudes. We fix M at 2 in this analysis.…”

“…Dibaryon-pole searches by the two-channel (pp, NLl) K(M)·matrix approach were performed by Edwards and. Thomas,),2) and by Bhandari et al 3) They have found poles in the area suggested by the single-channel analyses in terms of the Breit-Wigner formula. Among criticisms cast upon these K-matrix analyses, one important but not fully examined point is the validity of the two-channel approximation.…”