dorsal/arxiv
View SchemaIn-medium dependence and Coulomb effects of the pion production in heavy ion collisions
| Authors | V. S. Uma Maheswari, C. Fuchs, Amand Faessler, L. Sehn, D. S. Kosov, Z. Wang |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/9706004 |
| URL | https://arxiv.org/abs/nucl-th/9706004 |
| DOI | 10.1016/S0375-9474(97)00646-5 |
| Journal | Nucl.Phys. A628 (1998) 669-685 |
Abstract
The properties of the high energy pions observed in heavy ion collisions, in particular in the system Au on Au at 1 GeV/nucleon are investigated. The reaction dynamics is described within the Quantum Molecular Dynamics (QMD) approach. It is shown that high energy pions freeze out early and originate from the hot, compressed matter. $N^*$--resonances are found to give an important contribution toward the high energy tail of the pion. Further the role of in-medium effects in the description of charged pion yields and spectra is investigated using a microscopic potential derived from the Brueckner G-matrix which is obtained with the Reid soft-core potential. It is seen that the high energy part of the spectra is relatively more suppressed due to in-medium effects as compared to the low energy part. A comparision to experiments further demonstrates that the present calculations describe reasonably well the neutral (TAPS) and charged (FOPI) pion spectra. The observed energy dependence of the $\pi^-/\pi^+$ ratio, i.e. deviations from the isobar model prediction, is due to Coulomb effects and again indicate that high energy pions probe the hot and dense phase of the reaction. These findings are confirmed independently by a simple phase space analysis.
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"abstract": "The properties of the high energy pions observed in heavy ion collisions, in\nparticular in the system Au on Au at 1 GeV/nucleon are investigated. The\nreaction dynamics is described within the Quantum Molecular Dynamics (QMD)\napproach. It is shown that high energy pions freeze out early and originate\nfrom the hot, compressed matter. $N^*$--resonances are found to give an\nimportant contribution toward the high energy tail of the pion. Further the\nrole of in-medium effects in the description of charged pion yields and spectra\nis investigated using a microscopic potential derived from the Brueckner\nG-matrix which is obtained with the Reid soft-core potential. It is seen that\nthe high energy part of the spectra is relatively more suppressed due to\nin-medium effects as compared to the low energy part. A comparision to\nexperiments further demonstrates that the present calculations describe\nreasonably well the neutral (TAPS) and charged (FOPI) pion spectra. The\nobserved energy dependence of the $\\pi^-/\\pi^+$ ratio, i.e. deviations from the\nisobar model prediction, is due to Coulomb effects and again indicate that high\nenergy pions probe the hot and dense phase of the reaction. These findings are\nconfirmed independently by a simple phase space analysis.",
"arxiv_id": "nucl-th/9706004",
"authors": [
"V. S. Uma Maheswari",
"C. Fuchs",
"Amand Faessler",
"L. Sehn",
"D. S. Kosov",
"Z. Wang"
],
"categories": [
"nucl-th"
],
"doi": "10.1016/S0375-9474(97)00646-5",
"journal_ref": "Nucl.Phys. A628 (1998) 669-685",
"title": "In-medium dependence and Coulomb effects of the pion production in heavy ion collisions",
"url": "https://arxiv.org/abs/nucl-th/9706004"
},
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