Role of baryon resonances in the $��^-p \to ne^+e^-$ reaction within an effective-Lagrangian model

We present a study of the reaction $��^-p \to ne^+e^-$ for $\sqrt{s}=1.49\,\textrm{GeV}$, including non-resonant Born terms and contributions of the $N(1440)$, $N(1520)$, $N(1535)$ resonances ($R$), using an effective-Lagrangian model, which we extended by a phenomenological phase factor at the $RN��$ vertex function. We give predictions for both the differential cross section $d��/dm$ and the spin density matrix elements of the virtual photon that decays into the lepton pair. In the studied energy range, the cross section is dominated by the Born and $N(1520)$ contributions.
22 pages, 6 figures; data files for Figures 2-6 are provided