Internal meson dominance forpp¯annihilation

The previously considered ${}_{}{}^3{}_{}{}^{}\mathrm{S}_1^{}{}_{}{}^{}$ internal fusion model of pp¯→YY¯, YY¯ ${}_{}{}^{\mathrm{*}}{}_{}{}^{}$, and $Y^{\mathrm{*}}$Y${¯}^{*}$ (Y denotes hyperon) at low energies is modified and thereby extended to also include pp¯→nn¯ and ${\Delta }^{++}$Δ${¯}^{--}$. It is assumed that the same nonperturbative mechanism that mixes the different qq¯ pairs within the neutral, nonstrange mesons is also responsible for the scattering, annihilation, and creation of qq¯ pairs within the baryon-antibaryon system. More specifically, we assume that processes qq¯→QQ¯ within the baryon-antibaryon system with q=d or u and Q=d, u, or s quarks is mediated by fusion of the qq¯ to a pseudoscalar or vector meson that also within the system decays into QQ¯. The ${}_{}{}^1{}_{}{}^{}\mathrm{S}_0^{}{}_{}{}^{}$ pseudoscalar-meson model disagrees with experiment whereas the ${}_{}{}^3{}_{}{}^{}\mathrm{S}_1^{}{}_{}{}^{}$ vector-meson fusion model is in reasonable agreement with it. As compared to the previously considered ${}_{}{}^3{}_{}{}^{}\mathrm{S}_1^{}{}_{}{}^{}$ internal fusion model the main change is an extension of the approximate agreement to the nonstrange final-state baryons. This is achieved since strange baryons in the model are only produced via the small ω-φ mixing.