Dynamical chiral symmetry breaking and a critical mass
Dynamical chiral symmetry breaking and a critical mass
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DOI：
10.1103/physrevc.75.015201
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发表时间：
2006-05
影响因子：
3.1
通讯作者：
Lei Chang;Yu-xin Liu;M. Bhagwat;C. Roberts;S. V. Wright
中科院分区：
文献类型：
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作者：
Lei Chang;Yu-xin Liu;M. Bhagwat;C. Roberts;S. V. Wright
在一个有界的、可测量的非负电流夸克质量区域上，QCD能隙方程的实际模型可以同时存在两个非等价的动力学手征对称破缺（DCSB）解和一个与Wigner模中手征对称的实现毫不含糊地相关的解.维格纳解和其中一个DCSB解会被一个夸克质量所破坏，当夸克质量超过一个临界值时，两个解都会消失。这个临界值也限制了幸存的DCSB解决方案具有手性扩展的域。因此，这个值可以被看作是一个上界，在这个上界中，围绕手征极限的流夸克质量的微扰展开对于物理量是一致有效的。对于由等质量流夸克组成的赝标介子，它对应的质量为${m}_{{0}^{\ensuremath{-}~0.45$ GeV。在我们的讨论中，我们使用了差距方程的两个DCSB解的性质，使得在存在非零电流质量的情况下，$\ensuremath{\langle}\overline{q}q\ensuremath{\rangle}$的有效定义成为可能。这种凝聚体的行为表明，手征对称性破缺的基本动力学分量随流夸克质量的增加而减少。
On a bounded, measurable domain of non-negative current-quark mass, realistic models of the QCD gap equation can simultaneously admit two nonequivalent dynamical chiral symmetry breaking (DCSB) solutions and a solution that is unambiguously connected with the realization of chiral symmetry in the Wigner mode. The Wigner solution and one of the DCSB solutions are destabilized by a current-quark mass, and both disappear when that mass exceeds a critical value. This critical value also bounds the domain on which the surviving DCSB solution possesses a chiral expansion. This value can therefore be viewed as an upper bound on the domain within which a perturbative expansion in the current-quark mass around the chiral limit is uniformly valid for physical quantities. For a pseudoscalar meson constituted of equal-mass current quarks, it corresponds to a mass ${m}_{{0}^{\ensuremath{-}}}~0.45$ GeV. In our discussion, we employ properties of the two DCSB solutions of the gap equation that enable a valid definition of $\ensuremath{\langle}\overline{q}q\ensuremath{\rangle}$ in the presence of a nonzero current mass. The behavior of this condensate indicates that the essentially dynamical component of chiral symmetry breaking decreases with increasing current-quark mass.