Pursuing QCD Phase Transition with Lattice QCD and Experimental Data

Abstract

We propose a new approach to search for the QCD phase transition in the density-temperature plane, in terms of the canonical partition function, Zns, by combining experimental and lattice numerical studies. We extract the Zns from the lattice QCD simulations and the RHIC (Relativistic Heavy Ion Collider) data, and construct the moments as a function of µ/T , where µ and T stand for chemical potential and temperature, respectively. We calculate also the Lee-Yang zeros of Z(ξ ) obtained from the Zns of the lattice QCD and the RHIC data, where Z and ξ ≡ exp(µ/T ) are the grand partition function and complex fugacity. We show how to calculate the Lee-Yang zeros with high precision. As a byproduct, we found clear signals of the Roberge–Weiss transition in the Lee-Yang zero diagram, which occur not only at the pure imaginary chemical potential, but spread into the complex regions with Im(µ) = k × 2π