Skewness, kurtosis, and the fifth and sixth order cumulants of net baryon-number distributions from lattice QCD confront high-statistics STAR data
Alexei Bazavov, Dennis Bollweg, Heng-Tong Ding, P. Enns, Jishnu Goswami, Prasad Hegde, Olaf Kaczmarek, F. Karsch, Rasmus Larsen, Swagato Mukherjee, H. Ohno, Péter Petreczky, Christian Schmidt, Sayantan Sharma, Patrick Steinbrecher
Abstract
We present new results on up to sixth-order cumulants of net baryon-number fluctuations at small values of the baryon chemical potential, ${\ensuremath{\mu}}_{B}$, obtained in lattice QCD calculations with physical values of light and strange quark masses. Representing the Taylor expansions of higher-order cumulants in terms of the ratio of the two lowest-order cumulants, ${M}_{B}/{\ensuremath{\sigma}}_{B}^{2}={\ensuremath{\chi}}_{1}^{B}(T,{\ensuremath{\mu}}_{B})/{\ensuremath{\chi}}_{2}^{B}(T,{\ensuremath{\mu}}_{B})$, allows for a parameter-free comparison with data on net proton-number cumulants obtained by the STAR Collaboration in the Beam Energy Scan at RHIC. We show that recent high-statistics data on skewness and kurtosis ratios of net proton-number distributions, obtained at a beam energy $\sqrt{{s}_{NN}}=54.4\text{ }\text{ }\mathrm{GeV}$, agree well with lattice QCD results on cumulants of net baryon-number fluctuations close to the pseudocritical temperature, ${T}_{pc}({\ensuremath{\mu}}_{B})$, for the chiral transition in QCD. We also present first results from a next-to-leading-order expansion of fifth- and sixth-order cumulants on the line of the pseudocritical temperatures.