Fate of the ρ – a1 mixing in dilepton production

Abstract

We investigate the effect of chiral mixing on dilepton production by combining the in-medium spectral function in the chiral effective field theory with the state-of-the-art fluid dynamical simulations. We compare the spectral functions with different chiral symmetry restoration scenarios: without chiral symmetry restoration, with chiral symmetry restoration, and the lowtemperature mixing theory extrapolated to high-temperature. We find that the scenario with proper chiral symmetry restoration that takes into account the degenerate ρ and a1 mesons leads to an increase of the yield in the window of 1.1 < M < 1.4 GeV. Whereas, the extrapolated low-temperature theorem leads to a substantial overestimate at M = 1.2 GeV.