| Autor: |
Zeeb, Gebhard, Bugaev, Kyrill A., Reuter, Philipp T., Stöcker, Horst |
| Jazyk: |
angličtina |
| Rok vydání: |
2005 |
| Předmět: |
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| Popis: |
A canonical partition function for the two-component excluded volume model is derived, leading to two di erent van der Waals approximations. The one is known as the Lorentz-Berthelot mixture and the other has been proposed recently. Both models are analysed in the canonical and grand canonical ensemble. In comparison with the one-component van der Waals excluded volume model the suppression of particle densities is reduced in these two-component formulations, but in two essentially di erent ways. Presently used multi-component models have no such reduction. They are shown to be not correct when used for components with di erent hard-core radii. For high temperatures the excluded volume interaction is refined by accounting for the Lorentz contraction of the spherical excluded volumes, which leads to a distinct enhancement of lighter particles. The resulting e ects on pion yield ratios are studied for AGS and SPS data. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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