HADES has published new paper in PRC: "Proton-number fluctuations in sqrt(sNN) = 2.4 GeV Au+Au collisions studied with the High-Acceptance DiElectron Spectrometer (HADES)". Moments and cumulants up to 4th orders as a function of centrality and phase-space bins are presented.
The QCD critical endpoint (CEP) is a very distinct feature of the phase diagram of nuclear matter, but it can presently not be located from first-principle calculations; experimental observations are needed to constrain its position. The HADES Collaboration measured cumulants and correlators for net-proton number fluctuations, the most important observable so far to search for the CEP. This extends experimental results below the lowest beam energies available at th RHIC accelerator in Brookhaven (USA) and will be useful to discern the possibility of a critical point in the QCD phase diagram. These investigations will be continued in future experiments at FAIR.
Phys. Rev. C 102, 024914 (2020)