We investigate dilepton production in transport-based approaches and show
that the baryon couplings of the ρ meson represent the most important
ingredient for understanding the measured dilepton spectra. At low energies (of
a few GeV), the baryon resonances naturally play a larger role and affect
already the vacuum spectra via Dalitz-like contributions, which can be captured
well in an on-shell-transport scheme. At higher energies, the baryons mostly
affect the in-medium self energy of the ρ, which is harder to tackle in
transport models and requires advanced techniques.Comment: 4 pages, 3 figures, PANIC 2014 proceeding