Abstract:With a view towards implementation in microscopic transport simulations of heavyion collisions, the properties of spin-isospin modes are studied in nuclear matter consisting of nucleons and ∆ isobars that interact by the exchange of π and ρ mesons. For a standard p-wave interaction and an effective g ′ short-range interaction, the dispersion relations for the spin-isospin modes, and the associated amplitudes, are calculated at various nuclear densities and temperatures, within the random-phase approximation. Quantities of physical interest are then extracted, including the total and partial ∆ decay widths and the ∆ cross sections in the nuclear medium. The self-consistent inclusion of the ∆ width has a strong effect on the ∆ cross sections at twice normal nuclear density, as compared with the result of ignoring the width. Generally, the obtained quantities exhibit a strong density dependence, but are fairly insensitive to the temperature, at least up to T = 25 MeV. Finally, it is described how these in-medium effects may be consistently included into microscopic transport simulations of nuclear collisions, and the improvements over previous approaches are discussed.