Role of meson-meson correlation effects in the NN → ϱπ annihilation process

Meson-meson correlation effects are investigated in the NN → ϱπ annihilation process using a realistic meson-exchange model for the ϱπ interaction determined previously, together with a conventional baryon-exchange transition model and a consistent NN interaction. For NN S-states, they have a drastic effect and bring the relative (1S03S1) branching ratio up to the experimental value, thus offering an explanation for the long-standing so-called “ϱπ” puzzle. For NN P-states, their effect is of minor importance, and discrepancies remain for those ratios involving annihilation from the NN(3PJ) state to ϱπ(l′ = 2).