摘要
In heavy ion collisions,the directed flow v1 is considered to be sensitive to the equation of state(EoS)of QCD matter,since it reveals the pressure gradients at the early stage of the collision evolution.The strength of the directed flow is characterized by the slope dv1/dy at mid-rapidity,which is obtained by a linear fit of v1 distribution.In the referenced v1 study[1],distribution of dv1/dy for net-proton has been proposed as a signature of first order phase transition between hadronic matter and quark gluon plasma[2].
