Probing the softest region of the nuclear equation of state

An attractive, energy-dependent mean-field potential for baryons is introduced in order to generate a soft region in the nuclear equation of state, as suggested by recent lattice QCD calculations of baryon-free matter at finite temperature. Based on a hadronic transport model, we find that although this equation of state has negligible effects on the inclusive hadronic spectra, it leads to a minimum in the energy dependence of the transverse collective flow and a delayed expansion of the compressed matter. In particular, the transverse flow changes its direction as the colliding system passes through the softest region in the equation of state.