Speaker
Description
Measurements of dileptons emitted from heavy-ion collisions provide insights into the properties of the created fireball. As leptons are unaffected by strong final-state interactions, they carry valuable information about the hot and dense medium formed in the early stages of the collision. The high baryon densities achieved in heavy-ion reactions at a few GeV induce significant medium effects on the spectral functions of vector mesons.
While short-lived $\rho$ mesons predominantly decay within the fireball, radiating thermal dileptons, a substantial fraction of $\omega$ mesons decay outside the fireball due to their longer lifetime. These decays produce dileptons following the vacuum line shape and thus the $\omega$ meson contributes with a mixture of thermal and vacuum rates to the dilepton spectrum. High-statistics data from Ag+Ag collisions at $\sqrt{s_{NN}} = 2.55$ GeV, measured by the HADES collaboration, may allow for the isolation of these two different contributions and enable studies of in-medium modifications of the $\omega$ meson spectral function in the experimental data.
This contribution presents a framework that describes the vector meson vacuum contributions using the shining method, while the thermal dilepton spectrum is determined via the coarse-graining model. Through this joint description of thermal and vacuum contributions of light vector mesons we achieve precise theoretical predictions of the invariant mass spectrum of dileptons in heavy-ion collisions within the few GeV energy range.
In addition, we investigate how the ratio of thermal to vacuum contributions varies with transverse momentum, as well as the overall dependence of the dilepton spectrum on the collision centrality.
| Is the talk given on behalf of the Collaboration? | no |
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| Topic area | Phase Transition |