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arXiv 0709.4507nucl-ex
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CERN SPS能区Pb+Pb中心碰撞中π介子对的玻色-爱因斯坦关联

Bose-Einstein correlations of pion pairs in central Pb+Pb collisions at CERN SPS energies

NA49 Collaboration

摘要:

在CERN SPS上用NA 49探测器测量了能量为20 A、30 A、40 A、80 A和158 AGeV的Pb+Pb中心碰撞中π介子对的玻色-爱因斯坦关联。关联函数是在纵向共同移动的“外侧长”参考系中作为反应前半球的快度和横向动量的函数测量的。半径和相关强度参数从高斯参数化拟合获得。结果表明,π源中强径向流的径向参数随横向动量的增加而减小。没有观察到显著的依赖于π介子对快度或束能量。静态和动态特性的π介子源得到同时拟合与爆炸波模型的半径参数和midrapidity横向动量谱。讨论了Pb+Pb碰撞的流体动力学模型和微观模型的预测。

英文摘要:

Measurements of Bose-Einstein correlations of pion pairs in central Pb+Pb collisions were performed with the NA49 detector at the CERN SPS for beam energies of 20A, 30A, 40A, 80A, and 158A GeV. Correlation functions were measured in the longitudinally co-moving ``out-side-long'' reference frame as a function of rapidity and transverse momentum in the forward hemisphere of the reaction. Radius and correlation strength parameters were obtained from fits of a Gaussian parametrization. The results show a decrease of the radius parameters with increasing transverse momentum characteristic of strong radial flow in the pion source. No striking dependence on pion-pair rapidity or beam energy is observed. Static and dynamic properties of the pion source are obtained from simultaneous fits with a blast-wave model to radius parameters and midrapidity transverse momentum spectra. Predictions of hydrodynamic and microscopic models of Pb+Pb collisions are discussed.

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