Resonance properties in nuclear matter

We analyze the formation and decay properties of nucleon resonances formed in heavy-ion collisions at 1–2 GeV/u within a microscopic transport approach. In case of Au+Au reactions the density of Δ resonances reaches 0.15 ${\mathrm{fm}}^{\mathrm{-}3}$ in the central cell for a time period of the order of 10 fm/c such that one can legitimately speak about resonance matter. The lifetime of the Δ’s is found to be shortened at high density by only 20% due to the in-medium channel Δ+N→N+N.