dorsal/arxiv
View SchemaDilepton Production from AGS to SPS Energies within a Relativistic Transport Approach
| Authors | E. L. Bratkovskaya, W. Cassing |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/9611042 |
| URL | https://arxiv.org/abs/nucl-th/9611042 |
| DOI | 10.1016/S0375-9474(97)00140-1 |
| Journal | Nucl.Phys.A619:413-446,1997 |
Abstract
We present a nonperturbative dynamical study of $e^+e^-$ production in proton-nucleus and nucleus-nucleus collisions from AGS to SPS energies on the basis of the covariant transport approach HSD. For p + Be reactions the dilepton yield for invariant masses $M \leq 1.4$ GeV is found to be dominated by the decays of the $\eta, \rho, \omega$ and $\Phi$ mesons at all energies from 10 -- 450 GeV. For nucleus-nucleus collisions, however, the dilepton yield shows an additional large contribution from $\pi^+\pi^-$, $K^+K^-$ and $\pi \rho$ channels. Systematic studies are presented for the 'free' meson mass scenario in comparison to a 'dropping' meson mass scenario at finite baryon density. We find that for 'dropping' meson masses the invariant dilepton mass range 0.35 GeV $\leq M \leq$ 0.65 GeV is increased in comparison to the 'free' meson mass scenario and that the data of the CERES-collaboration for nucleus-nucleus collisions can be described much better within the 'dropping' mass scheme. We study in detail the contributions from the various dilepton channels as a function of the transverse momentum and rapidity of the lepton pair as well as a function of the charged particle multiplicity. Furthermore, various direct photon channels for S + Au at 200 GeV/u are computed and found to be well below the upper bounds measured by the WA80-collaboration.
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"abstract": "We present a nonperturbative dynamical study of $e^+e^-$ production in\nproton-nucleus and nucleus-nucleus collisions from AGS to SPS energies on the\nbasis of the covariant transport approach HSD. For p + Be reactions the\ndilepton yield for invariant masses $M \\leq 1.4$ GeV is found to be dominated\nby the decays of the $\\eta, \\rho, \\omega$ and $\\Phi$ mesons at all energies\nfrom 10 -- 450 GeV. For nucleus-nucleus collisions, however, the dilepton yield\nshows an additional large contribution from $\\pi^+\\pi^-$, $K^+K^-$ and $\\pi\n\\rho$ channels. Systematic studies are presented for the \u0027free\u0027 meson mass\nscenario in comparison to a \u0027dropping\u0027 meson mass scenario at finite baryon\ndensity. We find that for \u0027dropping\u0027 meson masses the invariant dilepton mass\nrange 0.35 GeV $\\leq M \\leq$ 0.65 GeV is increased in comparison to the \u0027free\u0027\nmeson mass scenario and that the data of the CERES-collaboration for\nnucleus-nucleus collisions can be described much better within the \u0027dropping\u0027\nmass scheme. We study in detail the contributions from the various dilepton\nchannels as a function of the transverse momentum and rapidity of the lepton\npair as well as a function of the charged particle multiplicity. Furthermore,\nvarious direct photon channels for S + Au at 200 GeV/u are computed and found\nto be well below the upper bounds measured by the WA80-collaboration.",
"arxiv_id": "nucl-th/9611042",
"authors": [
"E. L. Bratkovskaya",
"W. Cassing"
],
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"doi": "10.1016/S0375-9474(97)00140-1",
"journal_ref": "Nucl.Phys.A619:413-446,1997",
"title": "Dilepton Production from AGS to SPS Energies within a Relativistic Transport Approach",
"url": "https://arxiv.org/abs/nucl-th/9611042"
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