The global search for the QCD critical point
CriticalQCD is an independent, community-oriented scientific resource tracking the evidence, theoretical developments, experimental efforts, open questions, challenges, methods, and resources in the worldwide search for the QCD critical point.
Current assessment
The existence of an experimentally accessible QCD critical point has not been established.
Several measurements show intriguing fluctuation and correlation structures, but their interpretation remains unresolved. CriticalQCD tracks both possible critical signatures and credible noncritical explanations.
Last scientific update: September 2026
The central question
Does strongly interacting matter possess a critical point at finite temperature and baryon density that can be accessed through heavy-ion collisions?
Answering this requires more than observing one non-monotonic quantity. A convincing case should connect multiple independent observables, quantitative theory, realistic dynamical evolution, and stringent noncritical baselines.
Current Status
What do experiments and theory presently tell us?
Evidence, uncertainties, competing interpretations, and the measurements that could change the picture.
Open Questions
What remains genuinely unresolved?
A living map of the theoretical, experimental, statistical, and phenomenological problems that still stand between interesting signals and a convincing conclusion.
Resources
Find important papers, reviews, public talks, experimental programs, software, lectures, and reproducibility resources.
What CriticalQCD brings together
Experiment
RHIC BES and FXT, SPS, HADES, FAIR/CBM, NICA and other high-baryon-density programs.
Observables
Conserved-charge cumulants, factorial cumulants, correlations, intermittency, momentum fluctuations, light nuclei, full distributions, and emerging probes.
Theory
Universality, lattice QCD, critical dynamics, hydrodynamics, statistical mechanics, transport, and effective descriptions.
Challenges
Finite statistics, conservation laws, volume fluctuations, acceptance, critical slowing down, hadronic evolution, detector effects, and model dependence.
Scientific principle
CriticalQCD does not begin from the assumption that a critical point must be present in the experimentally accessible region.
The objective is to determine what the total body of evidence supports.
A credible conclusion should survive:
- multiple independent observables,
- realistic noncritical baselines,
- detector and analysis effects,
- dynamical evolution,
- quantitative theoretical consistency,
- and independent experimental confirmation.
Finding compelling evidence against an accessible critical point would be scientifically as important as establishing evidence for one.
A living scientific resource
CriticalQCD will grow continuously as new measurements, calculations, talks, software, and theoretical developments appear.