2018/01/31 by Zhibin Li, Kun Xu, Xinyang Wang +1
Physics and Astronomy · #Baryon #Baryon number #Critical line #Critical point (mathematics) #High-Energy Particle Collisions Research #Kurtosis #Lattice (music) #Line (geometry) #Phase (matter) #Physics of Superconductivity and Magnetism #Quantum Chromodynamics and Particle Interactions #hep-ph #hep-th
paper · pdf · doi:10.1140/epjc/s10052-019-6703-x
15 pages, 10 figures
openalex created_date 2018/07/10 · arxiv created 2019/01/29 · openalex publication_date 2019/03/01 · arxiv updated 2019/03/27 · openalex updated_date 2026/08/05
Firstly we qualitatively analyze the formation of the dip and peak structures of the kurtosis κ σ 2 of net baryon number fluctuation along imagined freeze-out lines and discuss the signature of the existence of the QCD critical end point (CEP) in the Nambu–Jona-Lasinio (NJL) model, Polyakov-NJL (PNJL) model as well as μ -dependent PNJL( μ PNJL) model with different parameter sets, and then we apply a realistic PNJL model with parameters fixed by lattice data at zero chemical potential, and quantitatively investigate its κ σ 2 along the real freeze-out line extracted from experiments. The important contribution from gluodynamics to the baryon number fluctuations is discussed. The peak structure of κ σ 2 along the freeze-out line is solely determined by the existence of the CEP mountain and can be used as a clean signature for the existence of CEP. The formation of the dip structure is sensitive to the relation between the freeze-out line and the phase boundary, and the freeze-out line starts from the back-ridge of the phase boundary is required. To our surprise, the kurtosis κ σ 2 produced from the realistic PNJL model along the experimental freeze-out line agrees with BES-I data well, which indicates that equilibrium result can explain the experimental data. It is worth to point out that the extracted freeze-out temperatures from beam energy scan measurement are indeed higher than the critical temperatures at small chemical potentials, which supports our qualitative analysis.