Existence and location of the QCD critical point · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title
Existence and location of the QCD critical point
Plain
At zero net baryon density, ordinary matter turns into quark-gluon plasma smoothly as it heats. At higher density the change may become abrupt, and the critical point is where smooth turns abrupt, if it exists.
Precise · changed · core
Revision 1: Determine whether the chiral crossover line $T_{\mathrm{pc}}(\mu_B)$ ($T_{\mathrm{pc}}(0)$ about $156\,\mathrm{MeV}$, $\mu_B$ the baryon chemical potential) ends at a critical point (T_c, mu_B,c) beyond which the transition is first order, and locate it. Lattice QCD disfavors a critical point at $\mu_B/T$ below about 3. Answer: yes or no, and (T_c, mu_B,c) with uncertainty.
Revision 2: Determine whether the chiral crossover line $T_{\mathrm{pc}}(\mu_B)$ ($T_{\mathrm{pc}}(0)$ about $156\,\mathrm{MeV}$, $\mu_B$ the baryon chemical potential) ends at a critical point $(T_c, \mu_B,c)$ beyond which the transition is first order, and locate it. Lattice QCD disfavors a critical point at $\mu_B/T$ below about 3. Answer: yes or no, and $(T_c, \mu_B,c)$ with uncertainty.
Settled by
A first-principles calculation reaching $\mu_B/T > 3$, or an experimentally established nonmonotonic fluctuation signal reproduced by dynamical critical-point modeling.
Kind
well-posed
Answer type
value
References
(empty)
Literature status
open
Status note
Functional-method and lattice-based extrapolations from 2021 to 2025 placed a possible critical point near $\mu_B$ of roughly 400 to 650 MeV, beyond direct lattice reach as of 2026.
Posed since
1989

Decisions