Energy Dependence of Moments of Net-Proton Multiplicity Distributions at RHIC

Abstract

We report the beam energy ( √ sNN = 7.7 -200 GeV) and collision centrality dependence of the mean (M ), standard deviation (σ), skewness (S), and kurtosis (κ) of the net-proton multiplicity distributions in Au+Au collisions. The measurements are carried out by the STAR experiment at midrapidity (|y| < 0.5) and within the transverse momentum range 0.4 < pT < 0.8 GeV/c in the first phase of the Beam Energy Scan program at the Relativistic Heavy Ion Collider. These measurements are important for understanding the Quantum Chromodynamic (QCD) phase diagram.

Critical behaviors near the (tri-)critical end point of QCD within the NJL model

“…For the case of finite current quark mass, the order parameter only carries one component, sigma (σ ), which is the only Fig. 5 The logarithm value of the quark number susceptibility as a function of log |μ − μ CEP | at the fixed temperature T CEP field becomes massless at the CEP. As is widely accepted, the phase transition falls into the three-dimensional (3D) Ising model as the liquid-gas phase transition [34][35][36].…”

“…This phase transition is expected to be a e-mail: zonghs@nju.edu.cn produced in on-going heavy-ion collision experiments, such as the BNL Relativistic Heavy-Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC) [5][6][7][8]. In addition, high density QCD matter at low temperature is anticipated in the compact stars physics [9][10][11].…”

Measurement of higher cumulants of net-charge multiplicity distributions inAu+Aucollisions atsNN=7.7Adare1, Afanasiev2, Aidala3 et al. 2016Phys. Rev. CSelf Cite790540View full textAdd to dashboardCite

“…From the energy dependence of µ/σ 2 , Sσ, κσ 2 , and Sσ 3 /µ, no obvious nonmonotonic behavior is observed. Although both previous measurements by STAR [32,33] use the pseudorapidity range |η| ≤ 0.5, compared to the present measurement spanning |η| ≤ 0.35, these measurements are all within the central rapidity region and are expected to be valid for comparison to lattice QCD calculations. The efficiency corrected results for the cumulant ratios µ/σ 2 , Sσ, and κσ 2 remain the same within statistics whether each single arm of the PHENIX central spectrometer (azimuthal aperture δφ = π/2) or both arms (δφ = π) are used.…”

Dynamic universality class of model H with frustrated diffusion: ε expansion

“…The conserved order parameter in this case comes from a linear combination of baryon charge and energy density. Although there has not been an experimental confirmation on the existence of the QCD critical point, there are tantalizing signals of baryon number cumulants observed in relativistic heavy-ion collision experiments in Relativistic Heavy-Ion Colliders (RHIC) [10], which seem to be consistent with what one would expect from the static universality class of 3D Ising model [11]. However, to draw more reliable conclusions from these encouraging results, we have to take into account that the quark-gluon plasma fireball created in such experiments is of finite size, and moreover it expands in time, which drives the system off-equilibrium.…”