Strangeness-Neutral Equation of State with an Ising-model Critical Point

We develop a family of strangeness-neutral Equations of State (EoS) for QCD, exhibiting critical behavior, matching the results on Taylor expansion coefficients from Lattice QCD, compatible with the SMASH hadronic transport approach, and in a range of temperature and baryonic chemical potential which is pertinent for phase II of the Beam Energy Scan at RHIC\footnote{D. Mroczek, A. R. Nava Acuna, J. Noronha-Hostler, P. Parotto, D. R. P. Price, C. Ratti, and J. M. Stafford, \textbf{Forthcoming publication}.}. With our implementation of strangeness neutrality conditions, the BES-EoS now serves to better reproduce the system in a heavy-ion collision, in which there is zero global strangeness density and a fixed ratio of electric charge to baryon number. In addition to the thermodynamic quantities that comprise the equation of state, we also show the isentropic trajectories and their transformations in a strangeness-neutral system, as well as the critical contribution to the correlation length. Finally, we compare our results with an earlier, non-strangeness-neutral version of the EoS\footnote{P. Parotto, M. Bluhm, D. Mroczek, M. Nahrgang, J. Noronha-Hostler, K. Rajagopal, C. Ratti, T. Schaefer, M. Stephanov, \textbf{ Phys. Rev.} C101 (2020) 034901.}.