Fate of the ρ – a₁ mixing in dilepton production

¹ Physics Program, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
² Department of Physics, Nagoya University, Nagoya, Aichi 464-8602, Japan
³ Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya, Aichi 464-8602, Japan
⁴ Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
⁵ International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM2), Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
⁶ Institute of Theoretical Physics, University of Wroclaw, plac Maksa Borna 9, PL-50204 Wroclaw, Poland

^* e-mail: azumi-sakai@hiroshima-u.ac.jp
^** e-mail: harada@hken.phys.nagoya-u.ac.jp
^*** e-mail: nchiho@hiroshima-u.ac.jp
^**** e-mail: chihiro.sasaki@uwr.edu.pl
^† e-mail: shigaki@hiroshima-u.ac.jp
^‡ e-mail: syano@hiroshima-u.ac.jp

Published online: 26 June 2024

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.