Non-Perturbative Analysis of Various Mass Generation by Gluonic Dressing Effect with the Schwinger-Dyson Formalism in QCD
Non-Perturbative Analysis of Various Mass Generation by Gluonic Dressing Effect with the Schwinger-Dyson Formalism in QCD
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DOI：
10.4236/jmp.2016.78073
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发表时间：
2014-01
期刊：
影响因子：
--
通讯作者：
S. Imai;H. Suganuma
中科院分区：
文献类型：
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作者：
S. Imai;H. Suganuma
作为“量子色动力学”的一个主题，我们利用（标量）QCD中的Schwinger-Dyson（SD）形式，在非微扰的条件下研究了各种色粒子的质量产生和胶子的修饰效应。首先，我们回顾了量子色动力学中的夸克质量产生的SD方法作为一个典型的费米子质量产生通过自发的手征对称性破缺。其次，利用标量QCD的SD形式，我们研究了标量双夸克（一种由两个夸克组成的类束缚态物体）及其质量产生，这显然是非手征起源的。在这里，标量双夸克被视为一个扩展的色标量场，就像有效强子模型中的介子，它的有效尺寸R被引入作为一个形状因子。与单夸克情形相比，标量双夸克情形的SD方程在数学上增加了一个四点相互作用项。双夸克的尺寸R小于强子，R ~ 1 fm，大于组分夸克，R ~ 0.3 fm。我们发现R ~ 0.3 fm的紧致双夸克具有约900 MeV的大有效质量，因此这种紧致双夸克在强子的有效模型中是不可接受的。我们还分别考虑了人工去除3点和4点相互作用的情况，以考察各个项的作用，发现4点相互作用对双夸克自能起主导作用。从夸克和双夸克这两种不同的情况，我们猜想色粒子的质量产生是非微扰胶子修饰效应的一般结果。
As a topic of “quantum color dynamics”, we study various mass generation of colored particles and gluonic dressing effect in a non-perturbative manner, using the Schwinger-Dyson (SD) formalism in (scalar) QCD. First, we review dynamical quark-mass generation in QCD in the SD approach as a typical fermion-mass generation via spontaneous chiral-symmetry breaking. Second, using the SD formalism for scalar QCD, we investigate the scalar diquark, a bound-state-like object of two quarks, and its mass generation, which is clearly non-chiral-origin. Here, the scalar diquark is treated as an extended colored scalar field, like a meson in effective hadron models, and its effective size R is introduced as a form factor. As a diagrammatical difference, the SD equation for the scalar diquark has an additional 4-point interaction term, in comparison with the single quark case. The diquark size R is taken to be smaller than a hadron, R ~ 1 fm, and larger than a constituent quark, R ~ 0.3 fm. We find that the compact diquark with R ~ 0.3 fm has a large effective mass of about 900 MeV, and therefore such a compact diquark is not acceptable in effective models for hadrons. We also consider the artificial removal of 3- and 4-point interaction, respectively, to see the role of each term, and find that the 4-point interaction plays the dominant role of the diquark self-energy. From the above two different cases, quarks and diquarks, we guess that the mass generation of colored particles is a general result of non-perturbative gluonic dressing effect.