Study of Ua(1) Breaking in Hadron Physics

强子物理中Ua(1)断裂的研究

• 批准号: 08640356
• 负责人: OKA Makoto
• 金额: $ 1.15万
• 依托单位: TOKYO INSTITUTE OF TECHNOLOGY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08640356/
• 关键词: strong interaction; QCD; chiral symmetry; meson; nucleon; Bethe-Salpeter equation; 軸性U(1)対称性; アノーマリー; エータ中間子; ベーテ・サルピータ方程式; 核子共鳴状態; ベ-テサルピーター方程式; SU(3)対称性; バドロン; 電磁崩壊

Chiral effective theories of QOD are applied to the hadron spectra and properties of hadrons at finite temperature and baryon density.We constructed an extended NJL model including a U(1)A breaking six-quark interaction vertex and found that a strong axial U(1) breaking is preferred phenomenological both in the meson and baryon sectors We also applied the improved ladder approximation in the Bethe-Salpeter equation for QCD and analyzed the pseudoscalar meson spectrum. The renormalization procedure is carried out for finite quark mass and an effective axialvector current is introduced so that the axial Ward-Takahashi identity is satisfied. Numerical calculation shows that the masses and decay constants of mesons are reproduced fairly well and the Gell-Mann-Oaks-Renner relation is satisfied for finite quark mass up to a hundred MeV.W also applied the QCD sum rule to the positive and negative parity baryons and showed explicitly that their mass difference comes from the chiral symmetry breaking. Two distinct assignments of chiral symmetry is shown to exhibit different behaviors of hadrons.

将手征有效QOD理论应用于有限温度和重子密度下的强子谱和强子性质.我们构造了一个包含U（1）A破缺的六夸克相互作用顶点的扩展NJL模型，发现在介子和重子扇区中，强轴向U（1）破缺都是唯象的.我们还在Bethe中应用了改进的梯形近似.量子色动力学的Salpeter方程，并分析了赝标介子谱。对有限质量的夸克进行了重整化处理，并引入了有效的轴向矢量流，使轴向Ward-Takahashi恒等式得到满足。数值计算表明，介子的质量和衰变常数得到了较好的再现，并且对于100 MeV以下的有限质量夸克，Gell-Mann-Oaks-Renner关系也得到了满足.W还将QCD求和规则应用于正、负宇称重子，明确地表明它们的质量差来自手征对称性破缺.两种不同的手征对称性分配显示出不同的强子行为。

项目成果

H.Kim: "Properties of N^*(1535) at Finite Density in the Exp.Parity-Doublet" Nuclear Physics. A640. 77-88 (1998)

H.Kim：“Exp.Parity-Doublet 中有限密度 N^*(1535) 的性质”核物理。

M.Ishida: "Possible Classification of Chiral Scalar sigma-Nonet" Prog.in Theor.Physics. 101. No.3 (1999)

M.Ishida：“手性标量 sigma-Nonet 的可能分类”Prog.in Theor.Physics。

M.Takizawa: "Present status of eta-eta' mixing angle" Soryushiron Kenkyu. 95. D153-D157 (1997)

M.Takizawa：“eta-eta混合角的现状”Soryushiron Kenkyu。

M.Takizawa: "Strong U_A(1) breaking in radiative η decays" Physical Review. D55. 4083-4097 (1997)

M.Takizawa：“辐射 η 衰变中的强 U_A(1) 断裂”物理评论 D55 (1997)。

Y.Nemoto: "η→π°γγ decay in the three-flavor Nambu-Jona-Lasinio model" Physical Review. D54. 6777-6781 (1996)

Y.Nemoto：“三味 Nambu-Jona-Lasinio 模型中的 η→π°γγ 衰变”《物理评论》D54（1996）。