Correlated $ππ$ and $K\bar K$ exchange in the baryon-baryon interaction

Abstract

A dynamical model for correlated two-pion and two-kaon exchange in the baryon- baryon interaction is presented, both in the scalar-isoscalar ($σ$) and the vector-isovector ($ρ$) channel. The correlations between the two pseudoscalar mesons are taken into account by means of $ππ- K\bar K$ amplitudes derived from a meson-exchange model, which is in line with the empirical $ππ$ data. It is found that correlated $K\bar K$ exchange plays an important role in the $σ$-channel for baryon-baryon states with non- vanishing strangeness. The strength of correlated $ππ$ plus $K\bar K$ exchange in the $σ$-channel decreases with the strangeness of the baryon- baryon system becoming more negative. The results for correlated $ππ$- exchange in the vector-isovector channel deviate from what is expected in the naive SU(3) picture for genuine $ρ$-exchange. Shortcomings of a simplified description in terms of sharp mass $σ$- and $ρ$-exchange are pointed out.