| Article | |
| Title | Understanding the properties of the fireball with the polarization signature of thermal dileptons |
| Author(s) | Seck, Florian (Darmstadt, Tech. U.) ; Friman, Bengt (Darmstadt, GSI ; Darmstadt, Tech. U.) ; Galatyuk, Tetyana (Darmstadt, GSI ; Darmstadt, Tech. U.) ; van Hees, Hendrik (Frankfurt U. ; Helmholtz Res. Acad. Hesse for FAIR) ; Speranza, Enrico (CERN) ; Rapp, Ralf (Texas A-M) ; Wambach, Jochen (Darmstadt, Tech. U.) |
| Publication | 2024 |
| Number of pages | 4 |
| In: | EPJ Web Conf. 296 (2024) 07009 |
| In: | 30th Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (Quark Matter 2023), Houston, Texas, United States of America, 3 - 9 Sep 2023, pp.07009 |
| DOI | 10.1051/epjconf/202429607009 |
| Subject category | Particle Physics - Phenomenology |
| Abstract | Multi-differential measurements of dilepton spectra serve as a unique tool to characterize the properties of matter in the interior of the hot and dense fireball created in heavy-ion collisions. An important property of virtual photons is their spin polarization defined in the rest frame of the virtual photon with respect to a chosen quantization axis. Microscopic calculations of in-medium electromagnetic spectral functions have mostly focused on integrated yields which are proportional to the sum of the longitudinal and transverse components of the virtual photon’s self-energy, while photon polarization results from the difference of these components. As the processes that drive the medium effects in the spectral function change with invariant mass and momentum, this becomes a powerful tool for studying the medium composition. We present the polarization observables of thermal virtual photons as a function of mass and momentum and confront the results with existing measurements from HADES and NA60. |
| Copyright/License | © 2024-2025 The author(s) (License: CC-BY-4.0) |
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Record created 2025-01-14, last modified 2025-01-15
