Köln 2025 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 42: Heavy-Ion Collisions and QCD Phases VII
HK 42.5: Vortrag
Donnerstag, 13. März 2025, 15:15–15:30, HS 3 Chemie
Proton and light nuclei number fluctuations measured at HADES — Marvin Nabroth and •Manuel Lorenz for the HADES collaboration — Goethe University, Frankfurt, Germany
QCD matter under extreme densities and moderate temperatures can be studied experimentally by conducting low-energy heavy-ion collisions.
The HADES (High-Acceptance Dielectron Spectrometer) experiment at SIS18/GSI is specifically designed to measure the reaction products of such collisions at kinetic beam energies in the 1 AGeV regime, thereby probing the freeze-out conditions at the highest baryon-chemical potentials. Net-baryon number fluctuations are a sensitive probe for investigating critical behavior expected near the conjectured first-order phase transition and the critical endpoint of the QCD phase diagram.
This report presents an analysis of proton and light nuclei multiplicity fluctuations measured in Ag+Ag collisions at √sNN = 2.55 GeV and Au+Au collisions at √sNN = 2.4 GeV. Advanced techniques for correcting detector inefficiencies and incomplete particle identification are discussed, including unfolding methods based on fuzzy logic and machine learning algorithms. Additionally, the effects of volume fluctuations and the corresponding correction strategies are covered.
Finally, we present the reconstructed cumulants of protons and light nuclei, along with their ratios, as functions of centrality and rapidity acceptance.
This work has been supported by BMBF (05P21RFFC2, 05H24RF5), GSI and HGS-Hire.
Keywords: HADES; heavy-ion collisions; high net-baryon density; fluctuations; protons and light nuclei