Effects of chain decays, radial flow and UA(1) restoration on the low-mass dilepton enhancement in √sN N =200 GeV Au+Au reactions

In √sN N =200 GeV Au+Au collisions PHENIX reported a significant enhancement in the low-mass region (0.1<mee<0.7 GeV) of the dielectron spectrum, which is still not fully understood. Several theoretical works and an indirect measurement suggest, due to the possible restoration of the UA(1) part of the chiral symmetry in a hot and dense medium, that the mass of the η′ meson may substantially decrease. This work reports on a statistically acceptable description of the PHENIX low-mass dilepton enhancement using a radial flow dominated meson spectra, chain decays of long-lived resonances and an in-medium η′ mass modification.