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arXiv 0812.3982hep-ph
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核子广义Adler-Weisberger求和规则与$Δ(1232)$的起源

Origin of Generalized Adler-Weisberger Sum Rule for the Nucleon and $Δ(1232)$

Keitaro Nagata

摘要:

利用$SU(2)_R\times SU(2)_L$不变拉格朗日量推导出包括$Δ(1232)$在内的核子和自旋3/2重子的轴向耦合常数的关系式。其中核子属于手征群的基本表象,而自旋为3/2的重子属于更高维的$(1,\half)\oplus (\half,1)$表象。由此产生的关系再现了一个来自广义Adler-Weisberger(GAW)求和规则的前向$πN$散射。我们澄清的起源GAW总和规则的核子和$Δ$考虑到群论方面和自发破缺的手征对称性。结果表明,核子和$Δ$的GAW求和规则是包含导数π-场和自发手征对称性破缺的相互作用存在的结果。这意味着在GAW求和规则中$N$和$Δ$之间的耦合随着手性缩合物朝向手性恢复的变化而消失。

英文摘要:

We derive a relation for the axial-coupling constants of the nucleon and spin-3/2 baryons including the $Δ(1232)$ with the use of an $SU(2)_R\times SU(2)_L$ invariant Lagrangian. Therein the nucleon belongs to the fundamental representation of the chiral group, while the spin-3/2 baryons belong to higher-dimensional representations $(1,\half)\oplus (\half,1)$. The resulting relation reproduces the one derived from the generalized Adler-Weisberger (GAW) sum rule for the forward $πN$ scattering. We clarify the origin of the GAW sum rule for the nucleon and $Δ$ by taking into account both the group-theoretical aspects and the spontaneous breaking of chiral symmetry. It turns out that the GAW sum rule for the nucleon and $Δ$ is a consequence of the existence of interactions involving a derivative-pion-field and spontaneous chiral symmetry breaking. This implies that the couplings between $N$ and $Δ$ in the GAW sum rule vanish with the change of the chiral condensate towards chiral restoration.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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