2013/03/09 by M. Vargyas, Vargyas, Marton
Physics and Astronomy · #FOS: Physical sciences #High-Energy Particle Collisions Research #Nuclear Experiment (nucl-ex) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.1303.2200
openalex publication_date 2013/03/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In case of an UA(1) symmetry restoration in a hot and dense hadronic matter,\nthe mass of the produced hadrons and mesons can significantly change, and their\nproduction cross-section can also be modified.\n In this M.Sc. Thesis I search for the signature of an eta' enhancement in the\nPHENIX dilepton spectrum in 200 GeV Au+Au collisions, which has a significant\nenhancement in the low-mass region, e.g. in the (0.1-1.0) GeV invariant\nelectron-positron mass range. This is also the region of the eta' meson's\nDalitz-decay (eta'->ee gamma), so the eta' enhancement might be responsible for\nat least a part of the excess. Other mesons' (other) properties can also be\nchanged in the hot, dense medium, but in this thesis I focus on the mass\nmodification of the eta' meson. To explore the role of eta', I used EXODUS\nsimulations to generate different dilepton spectra, corresponding to different\neta' properties. The conclusion here was that the excess can not be described\nwith just the eta' mass modification, but the agreement with data has been\nimproved significantly.\n Another idea which might brings us closer to understand the excess is to\nexamine the radial flow of the mesons, which was not included in the original\nPHENIX analysis. Radial flow is important in the low-pT range, where it\ndescribes the particles' spectra well: just in the region where the dilepton\nspectrum has the most contributions from. Thus examining the effect of the\nradial flow seems to be inevitable, as it might be responsible for certain\nparts of the excess.\n The results summarized here are work in progress, obtained with the framework\nof the PHENIX Collaboration at RHIC.\n