$P$-wave dibaryon resonances in $pp$ elastic scattering and near-threshold pion production

Abstract

It is demonstrated within the dibaryon-induced model for N N interaction that pp scattering in P waves is governed mainly by the production of the intermediate dibaryon resonances. Two dibaryon resonances with a mass of about 2200 MeV discovered recently by the ANKE-COSY Collaboration are shown to determine both elastic pp phase shifts and inelasticities in the 3 P0 and 3 P2-3 F2 channels from zero energy up to Tp = 0.7-0.9 GeV. It is also demonstrated clearly that the 3 P0 dibaryon plays a decisive role in near-threshold neutral pion production in pp collisions which is poorly understood to date. The missing dibaryon contribution is found to be the very possible reason for the failure of traditional approaches to explain near-threshold π 0 production.

Dibaryons: Molecular versus compact hexaquarks *

“…The question arises as to whether an intermediate formation of isoscalar dibaryon states such as in the course of the interaction between the nucleons in the nucleus may be an explanation for this phenomenon. This would be in line with the -interaction ansatz by Kukulin et al, where the short-and intermediate range part of the -interaction is assumed to be due to virtual -channel dibaryon formation [157][158][159]. In fact, inclusion of leads to a quantitative description of the phase shifts in both its real and imaginary parts [160].…”

“…In fact, inclusion of leads to a quantitative description of the phase shifts in both its real and imaginary parts [160]. Similar good results are obtained for most of the partial waves with low orbital momentum when the -coupled dibaryon states given in Table 2 are included [119,[158][159][160]. Because appears to exist in nuclear matter, it can influence the nuclear equation of state, especially in compact stellar objects such as neutron stars.…”