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arXiv 0709.0126nucl-thnucl-ex
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基于统计方法的快度相关化学势

Rapidity-dependent chemical potentials in a statistical approach

Wojciech Broniowski, Barlomiej Biedron

摘要:

我们提出了一个单冻结模型,热参数和几何参数依赖于火球内的位置,并使用它来描述的速度和横动量谱的π介子,K介子,质子和反质子在RHIC在200 GeV的BRAHMS测量。THERMINATOR用于执行必要的仿真,其中包括所有谐振衰减。拟合的结果是重子和奇异化学势随空间快度α_ \parallel的增长。在α_ \parallel ~ 3处的重子化学势值约为200 MeV,即处于SPS最高能量范围内。当α_ \parallel的大小增加时,所选择的火球几何形状具有减小的横向尺寸,这也对应于减小的横向流动。从K+/K-比拟合得到的奇异化学势使得火球中的局部奇异密度与零相容。由此产生的净质子的快度谱定性描述内的统计方法。作为我们研究的结果,获得了火球的“地形”知识,允许其他分析和预测。

英文摘要:

We present a single-freeze-out model with thermal and geometric parameters dependent on the position within the fireball and use it to describe the rapidity and transverse-momentum spectra of pions, kaons, protons, and antiprotons measured at RHIC at 200 GeV} by BRAHMS. THERMINATOR is used to perform the necessary simulation, which includes all resonance decays. The result of the fit to the data is the expected growth of the baryon and strange chemical potentials with the spatial rapidityα_\parallel. The value of the baryon chemical potential at α_\parallel ~ 3 is about 200 MeV, i.e. lies in the range of the highest SPS energies. The chosen geometry of the fireball has a decreasing transverse size as the magnitude of α_\parallel is increased, which also corresponds to decreasing transverse flow. The strange chemical potential obtained from the fit to the K+/K- ratio is such that the local strangeness density in the fireball is compatible with zero. The resulting rapidity spectra of net protons are described qualitatively within the statistical approach. As a result of our study, the knowledge of the ``topography'' of the fireball is acquired, allowing for other analyses and predictions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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