Journal article

Publication year: 1990

Pages: 615-638

Journal: Nuclear Physics A: Nuclear and Hadronic Physics

Volume number: 517

Issue number: 3-4

ISSN: 0375-9474

DOI Link: https://doi.org/10.1016/0375-9474(90)90222-8

Publisher: Elsevier

Abstract: 

The dynamical evolution of nucleus-nucleus collisions is described by a transport equation of the Uehling-Uhlenbeck type. Our model evolves phase-space distribution functions for nucleons, Δ's, N^∗(1440)-resonances and pions with their isospin degrees of freedom. The equations are solved by the test-particle simulation method. We apply this model to proton-nucleus and nucleus-nucleus collisions from 400 MeV/A to 2.1 GeV/A. Our approach is found to correctly describe the spectra of baryons and pions. Furthermore, we calculate the production of dileptons considering proton-neutron and pion bremsstrahlung, Δ and N^∗ decay and π⁺π⁻ annihilation. The calculations reproduce the data for p+⁹Be and for ⁴⁰Ca + ⁴⁰Ca at the bombarding energies of 1 GeV/A and 2 GeV/A except for small invariant masses (M⩽ 200 MeV) where the situation is not fully understood. Above 300 MeV dilepton invariant mass the relevant contributions arise from proton-neutron bremsstrahlung, the Δ Dalitz-decay and π⁺ π⁻ annihilation. At 2 GeV/A for ⁴⁰Ca + ⁴⁰Ca, however, we find the bremsstrahlung contribution to be higher than that from pion annihilation.

Harvard Citation style: Wolf, G., Batko, G., Cassing, W., Mosel, U., Niita, K. and Schäfer, M. (1990) Dilepton production in heavy-ion collisions, Nuclear Physics A: Nuclear and Hadronic Physics, 517(3-4), pp. 615-638. https://doi.org/10.1016/0375-9474(90)90222-8

APA Citation style: Wolf, G., Batko, G., Cassing, W., Mosel, U., Niita, K., & Schäfer, M. (1990). Dilepton production in heavy-ion collisions. Nuclear Physics A: Nuclear and Hadronic Physics. 517(3-4), 615-638. https://doi.org/10.1016/0375-9474(90)90222-8