On the critical end point of QCD

Abstract

We investigate the critical end point of QCD with two flavours of light dynamical quarks at finite lattice cutoff $a=1/4T$ using a Taylor expansion of the baryon number susceptibility. We find a strong volume dependence of its radius of convergence. In the large volume limit we obtain ${\ensuremath{\mu}}_{B}/T\ensuremath{\approx}1.1$ as the radius of convergence at $T/{T}_{c}\ensuremath{\approx}0.95$ where ${T}_{c}$ is the crossover temperature at zero chemical potential. Since this estimate is a lower bound on the critical end point of QCD, the above small value of $\ensuremath{\mu}$ may place it in the range of observability in energy scans at the Relativistic Heavy-Ion Collider (RHIC).