Does the NJL chiral phase transition affect the elliptic flow of a fluid at fixed η/s?
Abstract
We have derived and solved numerically the Boltzmann-Vlasov transport equations that includes both two-body collisions and the chiral phase transition by mean of NJL-field dynamics. The scope is to understand if the field dynamics supply new genuine effects on the build-up of the elliptic flow v2, a measure of the asymmetry in the momentum space, and in particular if it can affect the relation between v2 and the shear viscosity to entropy ratio η/s. Solving the transport equation with a constant cross section for the condition of Au+Au collisions at sNN=200 AGeV it is shown a sizable suppression of v2 due to the attractive nature of the field dynamics that generates the constituent mass. However the key result is that if η/s of the system is kept fixed by an appropriate local renormalization of the cross section the v2 does not depend on the details of the collisional and/or field dynamics and in particular it is not affected significantly by the chiral phase transition.