Intermediate mass excess of dilepton production in heavy ion collisions at BEVALAC energies
- Dielectron mass spectra are examined for various nuclear reactions recently measured by the DLS collaboration. A detailed description is given of all dilepton channels included in the transport model UrQMD 1.0, i.e. Dalitz decays of π, η, ω, ή mesons and of the (1232) resonance, direct decays of vector mesons and pn bremsstrahlung. The microscopic calculations reproduce data for light systems fairly well, but tend to underestimate the data in pp at high energies and in pd at low energies. These conventional sources, however, cannot explain the recently reported enhancement for nucleus-nucleus collisions in the mass region 0.15GeV ≤ Me+e- ≤ 0.6GeV. Chiral scaling and ω meson broadening in the medium are investigated as a source of this mass excess. They also cannot explain the recent DLS data.
| Verfasserangaben: | Christoph Ernst, Steffen A. BassORCiDGND, Mohamed Belkacem, Horst StöckerORCiDGND, Walter GreinerGND |
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| URN: | urn:nbn:de:hebis:30-23281 |
| Dokumentart: | Preprint |
| Sprache: | Englisch |
| Datum der Veröffentlichung (online): | 16.12.2005 |
| Jahr der Erstveröffentlichung: | 1998 |
| Veröffentlichende Institution: | Universitätsbibliothek Johann Christian Senckenberg |
| Datum der Freischaltung: | 16.12.2005 |
| Freies Schlagwort / Tag: | Dielektron; Kollisionen schwerer Ionen; Massenspektrum; UrQMD Dielectron; UrQMD; heavy ion collisions; mass spectra |
| Quelle: | Phys.Rev.C58:447-456,1998, http://arxiv.org/abs/nucl-th/9712069 Version 2 |
| HeBIS-PPN: | 185335446 |
| Institute: | Physik / Physik |
| DDC-Klassifikation: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
| Lizenz (Deutsch): |  Deutsches Urheberrecht |
