Charmonium spectral functions with the variational method in zero and finite temperature lattice QCD
Charmonium spectral functions with the variational method in zero and finite temperature lattice QCD
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DOI：
10.1103/physrevd.84.094504
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发表时间：
2011-04
影响因子：
5
通讯作者：
H. Ohno;S. Aoki;S. Ejiri;K. Kanaya;Y. Maezawa;H. Saito;T. Umeda
中科院分区：
文献类型：
--
作者：
H. Ohno;S. Aoki;S. Ejiri;K. Kanaya;Y. Maezawa;H. Saito;T. Umeda
我们提出了一种基于变分方法的计算格子上的谱函数的方法。在有限空间范围的格子上，谱函数只由离散谱组成。采用变分方法，计算了谱函数在低位离散谱上的位置和高度。我们首先在零温和有限温可解析可解的威尔逊自由夸克的情况下测试了该方法，并证实该方法很好地再现了低能谱的解析结果。我们发现，我们可以通过增加试验状态的数量来系统地改进结果。然后，我们用该方法计算了猝灭QCD中零温下S态和P波态的特征谱函数，并与传统的最大熵方法的结果进行了比较。基态的结果与MEM谱函数的第一峰的位置和面积是一致的，而变分方法得到的质量更接近于第一激发态的实验值。我们还研究了低于和高于T{subc}的S波态的谱函数与温度的关系。我们没有得到J/{psi}和{eta}{subc}直到1.4T{subc}的更多解离的明显证据。
We propose a method to evaluate spectral functions on the lattice based on a variational method. On a lattice with a finite spatial extent, spectral functions consist of discrete spectra only. Adopting a variational method, we calculate the locations and the heights of spectral functions at low-lying discrete spectra. We first test the method in the case of analytically solvable free Wilson quarks at zero and finite temperatures and confirm that the method well reproduces the analytic results for low-lying spectra. We find that we can systematically improve the results by increasing the number of trial states. We then apply the method to calculate the charmonium spectral functions for S and P-wave states at zero-temperature in quenched QCD and compare the results with those obtained using the conventional maximum entropy method (MEM). The results for the ground state are consistent with the location and the area of the first peak in spectral functions from the MEM, while the variational method leads to a mass which is closer to the experimental value for the first excited state. We also investigate the temperature dependence of the spectral functions for S-wave states below and above T{sub c}. We obtain no clear evidences formore » dissociation of J/{psi} and {eta}{sub c} up to 1.4T{sub c}.« less