We present measurements of bulk properties of the matter produced in Au+Au collisions at $\sqrt{s_{NN}}=7.7,11.5,19.6,27$, and 39 GeV using identified hadrons (${\pi }^{\pm }$, $K^{\pm }$, $p$, and $\overline{p}$) from the STAR experiment in the Beam Energy Scan (BES) Program at the Relativistic Heavy Ion Collider (RHIC). Midrapidity ($\left|y\right|<0.1$) results for multiplicity densities $dN/dy$, average transverse momenta $\langle p_T\rangle$, and particle ratios are presented. The chemical and kinetic freeze-out dynamics at these energies are discussed and presented as a function of collision centrality and energy. These results constitute the systematic measurements of bulk properties of matter formed in heavy-ion collisions over a broad range of energy (or baryon chemical potential) at RHIC.

• Received 25 January 2017

DOI:https://doi.org/10.1103/PhysRevC.96.044904