$NN \to NN π$ reaction near threshold in a covariant one-boson-exchange model

Abstract

We calculate the cross sections for the $p(p,nπ^{+})p$ and $p(p,pπ^{0})p$ reactions for proton beam energies near threshold in a covariant one-boson-exchange model, which incorporates the exchange of $π$, $ρ$, $σ$ and $ω$ mesons and treats both nucleon and delta isobar as intermediate states. The final state interaction effects have also been included. The $ω$ meson exchange is found to contribute significantly at these energies, which, along with other meson exchanges, provides an excellent agreement with the data. The cross sections at beam energies $\leq$ 300 MeV are almost free from the contributions of the $Δ$ isobar excitation.