Effects of N*(1440) resonance on particle production in heavy-ion collisions at subthreshold energies

We study quantitatively the effects of the N^*(1440) resonance on the production of kaons, antikaons, and antiprotons in heavy-ion collisions at subthreshold energies. It is found that baryon-baryon collisions involving the N^* have minor effects on the production of kaons and antikaons. For the production of antiprotons—considerably different from the previous finding that baryon-baryon collisions involving the Δ(1232) dominate—we found that collisions involving the N^* are at least equally important as those involving the Δ. Medium effects such as the broadened resonance widths and decreased masses of nucleons and antinucleons are also discussed.