Locating the QCD critical point with neutron-star observations

TL;DR

This paper combines neutron-star observations with advanced theoretical models to locate the QCD critical point, revealing a strong first-order transition and estimating the critical endpoint's position in the phase diagram.

Contribution

It introduces a probabilistic framework integrating holographic QCD and nuclear matter models constrained by astrophysical data to identify the QCD critical point.

Findings

Strong first-order deconfinement transition at zero temperature

Estimated critical endpoint at μ=626^{+90}_{-179} MeV, T=119^{+14}_{-6} MeV

Generated ensemble of EOSs with nuclear theory uncertainties

Abstract

We present a probabilistic model for the QCD critical endpoint (CEP) and the equation of state (EOS) at $\beta$-equilibrium, constrained by neutron-star observations. Using a hybrid framework that combines the holographic V-QCD model with an effective van der Waals description of nuclear matter, we generate a large ensemble of EOSs incorporating nuclear theory uncertainties. Constraining this ensemble with neutron-star mass-radius data and tidal deformability measurements from gravitational waves, we identify a strong first-order deconfinement transition at zero temperature, with a transition strength of $\Delta n_{\rm{PT}}/n_0 = 3.75^{+0.70}_{-0.53}$ and onset density $n_{\rm{PT}}/n_0 = 4.9^{+1.33}_{-1.17}$. The resulting posterior yields $95\%$ credible intervals for the CEP location: $\mu_{\rm{crit}} = 626^{+90}_{-179}\,\rm{MeV}$, $T_{\rm{crit}} = 119^{+14}_{-6}\,\rm{MeV}$.