From Sideward Flow to Nuclear Compressibility

Abstract

The authors use the transport model (BUU) with different optical potentials, combining density and momentum dependence with strong or weak nuclear compressibility, to simulate heavy-ion collisions. Experiment by DIOGENE allows them to show that experimental sideward flow is close to their calculations using optical potential of soft momentum- and density-dependence (Potential I), as well as calculations using optical potential of stiff pure density-dependence (Potential II). On the other hand, the Plastic Ball experiment on sideward flow, mainly due to the instrumental rejection of low transverse momentum particles, allows the authors to tell the differences between Potential I and II, with calculations using Potential I being close to the experimental data. Combining the results above, they see that only potential I with soft nuclear compressibility can describe the experimental data. The uncertainty of NN cross section in the medium leads to the uncertainty in nuclear compressibility, they estimate that the nuclear compressibility K lies between 180 and 235 MeV.