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. Dali
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.
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Metadaten
Author:Christoph Ernst, Steffen A. Bass, Mohamed Belkacem, Horst Stöcker, Walter Greiner
URN:urn:nbn:de:hebis:30-23281
Document Type:Preprint
Language:English
Date of Publication (online):2005/12/16
Year of first Publication:1998
Publishing Institution:Univ.-Bibliothek Frankfurt am Main
Release Date:2005/12/16
Tag:Dielektron ; Kollisionen schwerer Ionen; Massenspektrum ; UrQMD
Dielectron ; UrQMD ; heavy ion collisions; mass spectra
Source:Phys.Rev.C58:447-456,1998, http://arxiv.org/abs/nucl-th/9712069 Version 2
HeBIS PPN:185335446
Institutes:Physik
Dewey Decimal Classification:530 Physik
Sammlungen:Universitätspublikationen
Licence (German):License Logo Veröffentlichungsvertrag für Publikationen

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