Charmonium at finite temperature in quenched lattice QCD
Charmonium at finite temperature in quenched lattice QCD
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DOI：
10.1140/epjcd/s2004-01-002-1
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发表时间：
2002-11
期刊：
影响因子：
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通讯作者：
T. Umeda;K. Nomura;H. Matsufuru
中科院分区：
文献类型：
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作者：
T. Umeda;K. Nomura;H. Matsufuru
摘要本文研究了有限温度下伪标量通道和矢量通道中的调和子相关器。为了在欧几里得时间方向上有足够的自由度，使用了各向异性格。我们将重点放在与强子相中基态对应的谱函数的低能量结构上，通过涂抹技术来增强该区域对相关器的贡献。我们采用了两种分析方法：最大熵法（MEM）用于提取谱函数而不假设特定形式，以估计谱函数的形状，以及根据MEM结果使用典型形式的标准χ2拟合分析，以进行更定量的评价。为了验证程序的适用性，我们首先分析了零温度下的涂抹相关器和点相关器。我们发现，通过缩短用于分析的区间（一种不可避免的情况），点相关器的MEM可靠性降低，而涂抹相关器的MEM可靠性仍然存在。然后分析了模糊的相关因子atT≃0.9 tck和1.1 tck。当AtT =0时，光谱函数表现出一个强的峰值，与质量基本相同的基态对应的δ函数很好地近似。当达到1.1Tc时，强峰结构在几乎相同的地方仍然存在，但宽度有限，只有几百MeV。这一结果表明，即使在定义相位中，相关器也具有非平凡结构。pac: 12.38。Gc Lattice QCD计算- 12.38。夸克-胶子等离子体
AbstractWe study charmonium correlators in pseudoscalar and vector channels at finite temperature using lattice QCD simulation in the quenched approximation. Anisotropic lattices are used in order to have sufficient numbers of degrees of freedom in the Euclidean temporal direction. We focus on the low energy structure of the spectral function, corresponding to the ground state in the hadron phase, by applying the smearing technique to enhance the contribution to the correlator from this region. We employ two analysis procedures: the maximum entropy method (MEM) for the extraction of the spectral function without assuming a specific form, to estimate the shape of the spectral function, and the standardχ2fit analysis using typical forms in accordance with the result of MEM, for a more quantitative evaluation. To verify the applicability of the procedures, we first analyze the smeared correlators as well as the point correlators at zero temperature. We find that by shortening thet-interval used for the analysis (a situation inevitable atT>0) the reliability of MEM for point correlators is lost, while it subsists for smeared correlators. Then the smeared correlators atT≃ 0.9Tcand 1.1Tcare analyzed. AtT≃ 0.9Tc, the spectral function exhibits a strong peak, well approximated by a delta function corresponding to the ground state with almost the same mass as atT=0. AtT≃ 1.1Tc, we find that the strong peak structure still persists at almost the same place as belowTc, but with a finite width of a few hundred MeV. This result indicates that the correlators possess a nontrivial structure even in the deconfined phase.PACS: 12.38.Gc Lattice QCD calculations – 12.38.Mh Quark-gluon plasma