Quark Matter 2019 - the XXVIIIth International Conference on Ultra-relativistic Nucleus-Nucleus Collisions

Measurement of the sixth-order cumulant of net-proton multiplicity distributions from the STAR experiment

4 Nov 2019, 17:40

20m

Wanda Han Show Theatre & Wanda Reign Wuhan Hotel

Poster Presentation QCD at finite temperature and baryon density Poster Session

Speaker

Toshihiro Nonaka (Univ. Tsukuba)

Description

Cumulants of conserved quantities are the powerful tools to study the QCD phase structure. According to the Lattice Gauge Theory calculations, at vanishing baryon chemical potential (${\mu }_B$) a "smooth crossover" for the transition from quark-gluon plasma to hadronic system occurs in heavy-ion collisions [1]. One of the possible experimental ways to search for the evidence is to analyze the higher-order cumulant ratios of net-baryon distributions from high-energy nuclear collisions. The sixth-order ($C_6$) to second-order ($C_2$) cumulant ratio of baryon number fluctuations is predicted to be negative at the freeze-out temperature if it is close to the chiral transition temperature [2]. Net-proton multiplicity distributions can be studied as a reasonable proxy for net-baryon distributions [3,4]. In this poster, we present the centrality dependence of net-proton $C_6/C_2$ at $\sqrt{s_{\mathrm{N}\mathrm{N}}}=$ 54.4 and 200 GeV from a high statistics Au+Au collisions data set in the STAR experiment. The transverse momentum and rapidity dependence of $C_6/C_2$ for net-proton distributions will be also discussed.

[1] Y. Aoki et al., Nature, 443 (2006) 675.
[2] B. Friman et al., Eur. Phys. J. C, 71 (2011) 1694.
[3] Y. Hatta, M. A. Stephanov, Phys. Rev. Lett. 91 (2003) 129901.
[4] M. Kitazawa, M. Asakawa, Phys. Rev. C 86 (2012) 024904.

Presentation materials

tnonaka_QM2019_poster.pdf