arXiv subjects

Zhi-Ming Li

Publications and source records attributed to Zhi-Ming Li.

3 recordsLinked to original sources

arXiv2021

The sixth order cumulant of net-proton number in Binomial distribution at $\sqrt{s_{NN}} = $ 200 GeV

It is proposed that ratios of the sixth order to the second order cumulant ($C_6/C_2$) of conserved quantities are sensitive to the chiral crossover transition. Recently, the negative $C_6/C_2$ was obtained both in theoretical Lattice QCD and experiments at $\sqrt{s_{NN}} = $ 200 GeV. In this study, we investigate the behavior of net-proton $C_6/C_2$ in statistical Binomial distribution (BD) at $\sqrt{s_{NN}} = $ 200 GeV in Au + Au collisions. With the BD parameters extracted from RHIC/STAR, it is found that $C_6/C_2$ can be negative. Furthermore, the obtained $C_6/C_2$ becomes smaller when applying the same magnitude of experimental statistics and calculation method to simulations. In 0-10\% centrality, there is a significant difference between the simulated result and theoretical expectation. Based on the extracted parameters and experimentally collected statistics, the baseline of net-proton $C_6/C_2$ in BD is presented.

nucl-th↗

arXiv2018

How to locate the QCD phase boundary by scanning observable in the phase plane

For small volume of the quark-gluon plasma formed in heavy ion collisions, the observable near criticality must obey finite-size scaling. According to the finite-size scaling, there exists a fixed point at the critical temperature, where scaled susceptibility at different system sizes intersect. It also exists at the transitional temperature of a first order phase transition and can be generalized to the region of the crossover. In order to quantify the feature of the fixed point, we introduce {\it the width of a set of points}. When all points in the set are in their mean position within error, the width reaches its minimum, and all points merge into the fixed point. Using the observable produced by the Potts model, we demonstrate that the contour plot of the width defined in this study clearly indicates the temperatures and exponent ratios of fixed point, which could correspond to either the critical point, the points on the transition line, or the crossover region. This method is therefore instructive to the determination of QCD phase boundary by beam energy scan in relativistic heavy ion collisions.

hep-ph↗

arXiv2017

High cumulants of conserved charges and their statistical uncertainties

We study the influence of measured high cumulants of conserved charges on their associated statistical uncertainties in relativistic heavy-ion collisions. With a given number of events, the measured cumulants randomly fluctuate with an approximately normal distribution, while the estimated statistical uncertainties are found to be correlated with corresponding values of the obtained cumulants. Generally, with a given number of events, the larger the cumulants we measure, the larger the statistical uncertainties that are estimated. The error-weighted averaged cumulants are dependent on statistics. Despite this effect, however, it is found that the three sigma rule of thumb is still applicable when the statistics are above one million.

nucl-th↗