Speaker
Description
We present a first measurement of low-mass electron pairs for a heavy collision-system at SIS18/Bevalac energies. The data is analyzed in terms of excess radiation above a conventional cocktail of contributions from meson decay after thermal freeze-out. We observe a strong excess radiation which is remarkably well described assuming emission from a thermalized system. The high statistics data allows studying multi-differential distributions. The multiplicity of excess radiation in the mass window 300 to 700 MeV/$c^2$ rises with $A_{part}$ stronger than linear. To gain deeper understanding of the microscopic origin of the excess radiation we started to investigate di-electron radiation emitted from baryonic resonances produced off protons in pion-induced reactions. The data is in support of VMD in electromagnetic transition of excited baryons.
| Preferred Track | Electromagnetic Probes |
|---|---|
| Collaboration | Other |
