Scaling In Heavy-ion Collisions And The Low-energy Frontier

Abstract

The common interpretation of elliptic flow v(2) in heavy-ion collisions is that it is produced by hydrodynamic flow at low transverse momentum and by parton energy loss at high transverse momentum. Here, we discuss this interpretation in view of the dependence of v(2) on energy, rapidity and system size, and show that it is far from clear how the relevant properties necessary for this interpretation, low viscosity and high opacity, turn on. A low-energy collider such as NICA is essential for this interpretation to be verified, understood and related to the fundamental properties of hadronic matter.

The common interpretation of elliptic flow v(2) in heavy-ion collisions is that it is produced by hydrodynamic flow at low transverse momentum and by parton energy loss at high transverse momentum. Here, we discuss this interpretation in view of the dependence of v(2) on energy, rapidity and system size, and show that it is far from clear how the relevant properties necessary for this interpretation, low viscosity and high opacity, turn on. A low-energy collider such as NICA is essential for this interpretation to be verified, understood and related to the fundamental properties of hadronic matter.