Mainz 2022 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 45: Heavy-Ion Collisions and QCD Phases IX
HK 45.1: Group Report
Wednesday, March 30, 2022, 16:00–16:30, HK-H1
Vector and Axial-Vector Mesons in Nuclear Matter — •Ralf-Arno Tripolt1, Tetyana Galatyuk2,3, Lorenz von Smekal1,4, Jochen Wambach2, and Maximilian Wiest2 — 1Justus Liebig University Giessen, Germany — 2TU Darmstadt, Germany — 3GSI, Darmstadt, Germany — 4Helmholtz Research Academy Hesse for FAIR (HFHF), Campus Giessen, Germany
We present recent results on the in-medium spectral functions of the rho(770) vector meson and the a1(1260) axial-vector meson in nuclear matter, as well as on the resulting thermal dilepton rate. As an effective description of the thermodynamics and the phase structure of nuclear matter we use a chiral baryon-meson model, taking into account the effects of fluctuations from scalar mesons, nucleons, and vector mesons within the Functional Renormalization Group (FRG) approach [1]. Our results show strong modifications of the spectral functions in particular near the chiral critical endpoint which suggest an enhanced dilepton yield at lower energies. Such an enhancement is also found in GiBUU transport simulations for C+C at 1A GeV when including effects of chiral symmetry restoration in the kinetic equations for baryon propagation [2]. Our results may therefore well be of relevance for electromagnetic rates in heavy-ion collisions or neutrino emissivities in neutron-star merger events and help to identify phase transitions and the critical endpoint.
[1] R.-A. Tripolt, C. Jung, L. von Smekal, J. Wambach, Phys. Rev. D 104, 054005 (2021)
[2] A. B. Larionov, L. von Smekal, arXiv: 2109.03556