Higher order cumulants of electric charge and strangeness fluctuations on the crossover line

Abstract

We present lattice QCD calculations of higher order cumulants of electric charge distributions for small baryon chemical potentials $\mu_B$ by using up to NNNLO Taylor expansions. Ratios of these cumulants are evaluated on the pseudo-critical line, $T_{pc}(\mu_B)$, of the chiral transition and compared to corresponding measurements in heavy ion collision experiments by the STAR and PHENIX Collaborations. We demonstrate that these comparisons give strong constraints on freeze-out parameters. Furthermore, we use strangeness fluctuation observables to compute the ratio $\mu_S/\mu_B$ on the crossover line and compare it to $\mu_S/\mu_B$ at freeze-out stemming from fits to strange baryon yields measured by the STAR Collaboration.