格点QCD中有限体积下形状因子的内插计算  

Lattice QCD Calculation of the Form Factor by Interpolation within Finite Volume

作　　者：张文昊 ZHANG Wenhao(Physics Department,Peking University,Beijing 100871,China)

机构地区：[1]北京大学物理学院,北京100871

出　　处：《原子核物理评论》2021年第2期136-146,共11页Nuclear Physics Review

摘　　要：在格点QCD的框架下,讨论了计算强子的形状因子的过程中,有限体积效应对所得结果的影响,并且给出了计算连续动量空间上形状因子数值的内插算法。本文以π介子的形状因子为例,介绍了从格点QCD中得到的三点关联函数出发计算π介子的形状因子的方法,并说明有限体积效应使得计算结果只能在分立动量上给出。本文探讨了一种保持旋转对称性的内插算法和一种对于傅立叶变换进行连续化的内插算法,基于分立的形状因子取值给出了连续动量空间上的形状因子,并且提供了模型模拟的结果与真实格点系统上的数值结果。本文提出的内插算法及数值模拟的结论不依赖于特定的格点系综,具有一定程度的普适性,能够推广到对于其他格点系统的有限体积效应的处理,同时为格点系统尺度的选取提供了有价值的参考。This paper discusses the finite-volume effect in calculating hadron form factors using lattice QCD framework.Taking Pion as the example,we introduce the method of extracting hadron form factors from three-point correlation functions computed in lattice QCD,but only at separated points in the momentum space because of the finite-volume effect.This paper gives one interpolation algorithm which respects rotation symmetry and also provides a sketch of another interpolation method which applies the continuous Fourier transform,both methods continuously giving form factor results on the momentum space based on the discrete values.These algorithms are examined under numerical models and realistic lattice systems.The results given by the interpolation are independent of specific systems and can be easily generalized to a variety of lattice systems.Our conclusion also provides valuable information which could help determining the proper size of lattice systems.

关 键 词：格点QCD 形状因子 内插法 有限体积效应 

分 类 号：O4[理学—物理]