Charmonium properties in deconfinement phase in anisotropic lattice QCD
Charmonium properties in deconfinement phase in anisotropic lattice QCD
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DOI：
10.1103/physrevd.74.074502
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发表时间：
2006-02
影响因子：
5
通讯作者：
H. Iida;T. Doi;N. Ishii;H. Suganuma;K. T. Yitp;U. Kyoto;R. Bnl;U. Tokyo
中科院分区：
文献类型：
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作者：
H. Iida;T. Doi;N. Ishii;H. Suganuma;K. T. Yitp;U. Kyoto;R. Bnl;U. Tokyo
在各向异性猝灭晶格QCD中，研究了临界温度T＿c以上的J/Psi和eta＿c，考虑了T＿c以上的c \bar c体系是空间紧致（准）束缚态还是散射态。我们在16^3个\times（14-26）晶格上采用标准的Wilson规范作用和O(a)改进的Wilson夸克作用，各向异性在\beta =6.10处a＿s/a＿t =4.0，对应于空间晶格体积V \equiv L^3 \simeq (1.55 {\rmfm})^3和温度T \simeq (1.11-2.07)T＿c。我们从具有空间扩展算子的时间相关器中研究了T＿c以上的c \bar c系统，其中与基态的重叠增强了。为了阐明紧谐态是否存在于定义阶段，我们研究了c \bar c系统在T＿c以上能量的空间边界条件依赖性。事实上，对于低s波c \bar c散射态，预计在有限体积晶格上，周期和反周期边界条件之间会出现显著的能量差异\Delta E \equiv E {\rm(APBC)}-E (PBC){\rm}\simeq 2 \sqrt{m_c^2+3\pi^2/L^2} -2m＿c （m＿c：粲夸克质量）。相反，对于紧谐态，周期边界条件和反周期边界条件之间没有显著的能量差。作为点阵QCD结果，对于T \simeq (1.11-2.07)T＿c，在J/ \Psi和\eta ＿c通道中，c \bar c体系的能量几乎没有空间边界条件依赖。这一事实表明，J/ \Psi和\eta ＿c在2T＿c以下作为空间紧凑的c \bar c（准）束缚态存在。我们还用最大熵法（MEM）研究了高温下的$P$ -波通道，发现在1.62T＿c处没有对应\chi ＿c1{的低洼峰结构。}
J/Psi and eta_c above the QCD critical temperature T_c are studied in anisotropic quenched lattice QCD, considering whether the c\bar c systems above T_c are spatially compact (quasi-)bound states or scattering states. We adopt the standard Wilson gauge action and O(a)-improved Wilson quark action with renormalized anisotropy a_s/a_t =4.0 at \beta=6.10 on 16^3\times (14-26) lattices, which correspond to the spatial lattice volume V\equiv L^3\simeq(1.55{\rm fm})^3 and temperatures T\simeq(1.11-2.07)T_c. We investigate the c\bar c system above T_c from the temporal correlators with spatially-extended operators, where the overlap with the ground state is enhanced. To clarify whether compact charmonia survive in the deconfinement phase, we investigate spatial boundary-condition dependence of the energy of c\bar c systems above T_c. In fact, for low-lying S-wave c \bar c scattering states, it is expected that there appears a significant energy difference \Delta E \equiv E{\rm (APBC)}-E{\rm (PBC)}\simeq2\sqrt{m_c^2+3\pi^2/L^2}-2m_c (m_c: charm quark mass) between periodic and anti-periodic boundary conditions on the finite-volume lattice. In contrast, for compact charmonia, there is no significant energy difference between periodic and anti-periodic boundary conditions. As a lattice QCD result, almost no spatial boundary-condition dependence is observed for the energy of the c\bar c system in J/\Psi and \eta_c channels for T\simeq(1.11-2.07)T_c. This fact indicates that J/\Psi and \eta_c would survive as spatially compact c\bar c (quasi-)bound states below 2T_c. We also investigate a $P$-wave channel at high temperature with maximally entropy method (MEM) and find no low-lying peak structure corresponding to \chi_{c1} at 1.62T_c.