# Quark Matter 2018

May 13 – 19, 2018
Venice, Italy
Europe/Zurich timezone
The organisers warmly thank all participants for such a lively QM2018! See you in China in 2019!

## Effect of Volume Fluctuation and Non-binomial Efficiency on the Cumulants of Net-proton Multiplicity Distributions at the STAR Experiment

May 15, 2018, 5:00 PM
2h 40m
First floor and third floor (Palazzo del Casinò)

### First floor and third floor

#### Palazzo del Casinò

Poster Correlations and fluctuations

### Speaker

Toshihiro Nonaka (Univ. Tsukuba)

### Description

Recent STAR results on net-proton cumulant ratio $C_{4}/C_{2}=\kappa\sigma^{2}$ show a non-monotonic behavior as a function of beam energy [1], which has been interpreted as a signature of the QCD critical end point. However, all previous STAR results were obtained with a binomial assumption for the efficiency correction. Unfolding of net-proton distributions is necessary in order to correct for non-binomial detector effects [2]. In addition, there are still no established ways for volume fluctuation corrections. Recently another model dependent method [3] has been suggested to eliminate the participant fluctuations. In this poster, we present the results of the unfolding method that attempts to correct for the non-binomial detector efficiencies and apply the new method for volume fluctuation corrections. The differences with respect to the previous results are discussed.

References
[1] Xiaofeng Luo (for the STAR collaboration), Proceedings, 9th International Workshop on Critical Point and Onset of Deconfinement (CPOD 2014), Vol. CPOD2014 (2015).
[2] A. Bzdak, R. Holzmann, and V. Koch, Phys. Rev. C94, 064907 (2016).
[3] P. Braun-Munzinger, A. Rustamov, and J. Stachel, Nucl. Phys. A960, 114130 (2017).

Collaboration STAR Experiment Presenter name already specified

### Primary author

Zhenyu Ye (University of Illinois at Chicago)