Second order cumulants of conserved charge fluctuations revisited: Vanishing chemical potentials
Dennis Bollweg, Jishnu Goswami, Olaf Kaczmarek, F. Karsch, Swagato Mukherjee, P. Petreczky, Christian Schmidt, Philipp Scior
Abstract
We update lattice QCD results for second order cumulants of conserved charge fluctuations and correlations at nonzero temperature and vanishing values of the conserved charge chemical potentials. We compare these results to hadron resonance gas calculations with and without excluded volume terms as well as S-matrix results in the hadronic phase of QCD and comment on their current limitations. We, furthermore, use these results to characterize thermal conditions in the vicinity of the pseudocritical line of the chiral transition in QCD. We argue that the ratio of strange to baryon chemical potentials is a robust observable that, on the one hand, deviates only little from hadron resonance gas results, but, on the other hand, is very sensitive to the spectrum of strange baryon resonances.