We calculate several diagonal and non-diagonal fluctuations of conserved charges in a system of 2+1+1 quark flavors with physical masses, on a lattice with size 483×12. Higher order fluctuations at μB=0 are obtained as derivatives of the lower order ones, simulated at imaginary chemical potential. From these correlations and fluctuations we construct ratios of net-baryon number cumulants as functions of temperature and chemical potential, which satisfy the experimental conditions of strangeness neutrality and proton/baryon ratio. Our results qualitatively explain the behavior of the measured cumulant ratios by the STAR collaboration.
@article{arxiv.1805.04445,
title = {Higher order fluctuations and correlations of conserved charges from lattice QCD},
author = {Szabolcs Borsanyi and Zoltan Fodor and Jana N. Guenther and Sandor K Katz and Kalman K. Szabo and Attila Pasztor and Israel Portillo and Claudia Ratti},
journal= {arXiv preprint arXiv:1805.04445},
year = {2018}
}