Experimental and theoretical indications for an intermediate σ-dressed dibaryon in the NN interaction

Abstract Numerous theoretical and experimental arguments in favor of the generation of intermediate σ -dressed dibaryon in NN interaction at middle and short distances are presented. We argue that this intermediate dibaryon should be responsible for the strong middle-range attraction and the short-range repulsion in the NN interaction, and also for the short-range correlations in nuclei. The suggested mechanism for the σ -dressing of the dibaryon is identical to that which explains the Roper-resonance structure, its dominant decay mode and its extraordinary low mass. It is arguing that the (partial) chiral symmetry restoration effects, common for the Roper resonance and dressed dibaryon, are responsible for strong renormalizing of their masses and widths and the observed σ -meson mass and decay width as well. The new experimental data on 2 π -production in the scalar–isoscalar channel produced in pn - and pd -collisions and recent data on γγ correlations in p C and d C scattering in the GeV region seems to corroborate the existence of the σ -dressed dibaryon in two- and three-nucleon interactions. A similar transformation mechanism from the glue to the scalar field can be valid also in some J / Ψ decays and in enormous σ -meson production in central pp collisions at high energies.