Criticality on the QCD phase diagram from lattice QCD

The main goal of the heavy ion program of many accelerator facilities (LHC, RHIC and the upcoming CBM/FAIR) is to create new phases of matter and explore their properties under extreme conditions. 

Several experimental programs (e.g. beam energy scans) are designed to search for a hypothetical critical end point in the phase diagram in the temperature-baryon density plane.

The project team explores the phase diagram using ab initio lattice QCD simulations. The team does so by performing simulations at zero and imaginary chemical potentials. 

First, it will calculate the transition temperature for high values of the baryon density, to locate the position in the phase diagram where the phenomenological freeze-out conditions separate from the chiral transition. Second, the team will calculate fluctuations of the baryon number at finite density, to look for signals of critical behaviour. The project will also perform a Bayesian analysis to obtain a posterior distribution for the possible locations of the elusive critical end point. 

The knowledge gained in this study will influence future decisions on the optimal setups (e.g. beam energies) in the experimental quest for criticality in strongly interacting matter.