Parity Doublet Model for Baryon Octets Based on the Quark-line Diagram  

基于夸克线图的重子八重态宇称双重态模型

作　　者：GAO Bikai KOJO Toru HARADA Masayasu 高毕凯;古城徹;原田正康(名古屋大学,日本名古屋466-8602;日本东北大学,日本仙台980-8578;素粒子宇宙起源研究所,日本名古屋319-1195;日本原子能研究开发机构,日本东海464-8602)

机构地区：[1]Nagoya University,Nagoya 466-8602,Japan [2]Department of Physics,Tohoku University,Sendai 980-8578,Japan [3]Advanced Science Research Center,Japan Atomic Energy Agency,Tokai 319-1195,Japan [4]Kobayashi-Maskawa Institute for the Origin of Particles and the Universe,Nagoya 464-8602,Japan

出　　处：《原子核物理评论》2024年第3期794-800,共7页Nuclear Physics Review

摘　　要：Parity doublet model is an effective chiral model that includes the chiral variant and invariant masses of baryons.The chiral invariant mass has large impacts on the density dependence of models which can be constrained by neutron star observations.In the previous work,models of two-flavors to few times nuclear saturation density have been considered,but in such dense region it is also necessary to consider hyperons.In this work,we construct SU(3)_(L)⊗SU(3)_(R)invariant parity doublet models within the linear realization of the chiral symmetry.The major problem in constructing such models has been too many candidates for the chiral representations of baryons.Motivated by the concepts of diquarks and the mended symmetry,we choose the(3_(L),3_(R))+(3_(L),3_(R)),(3_(L),6_(R))+(6_(L),3_(R))and(1_(L),8_(R))+(8_(L),1_(R))representations and use quark diagrams to constrain the possible types of Yukawa interactions.The masses of the baryon octets for positive and negative baryons up to the first excitations are successfully reproduced.As expected from the diquark considerations,the ground state baryons are well dominated by(3_(L),3_(R))+(3_(L),3_(R))and(1_(L),8_(R))+(8_(L),1_(R))representations,while the excited states require(3_(L),6_(R))+(6_(L),3_(R))representations.The model should be useful to consider the chiral restoration for strange quarks at large density and the continuity of diquarks from hadronic to quark matter.宇称双重态模型是一种有效的手征模型,包含了重子的手征变量质量和手征不变质量。手征不变质量对模型的密度依赖性有很大影响,可以通过中子星的观测来约束。在之前的工作中,已经考虑了核饱和密度几倍范围内的两味模型,但在如此高的密度下,也有必要考虑超子。在本工作中,在手征对称性的线性框架内构建了SU(3)_(L)⊗SU(3)_(R)不变的宇称双重态模型。构建这类模型的主要问题是重子的手征表示候选太多。受到双夸克和手征对称性概念的启发,选择了(3_(L),3_(R))+(3_(L),3_(R)),(3_(L),6_(R))+(6_(L),3_(R))和(1_(L),8_(R))+(8_(L),1_(R))的重子手征表示,并使用夸克图来约束可能的Yukawa相互作用类型。成功地重现了正宇称和负宇称重子八重态的质量,直至第一激发态。正如双夸克考虑所预期的那样,基态重子主要由(3_(L),3_(R))+(3_(L),3_(R))和(1_(L),8_(R))+(8_(L),1_(R))表示主导,而激发态则需要包含(3_(L),6_(R))+(6_(L),3_(R))来解释。该模型对于考虑高密度下奇异夸克的手征恢复以及从强子物质到夸克物质的双夸克连续性提供了基础框架。

关 键 词：parity doublet chiral symmetry quark diagram neutron star HYPERON 

分 类 号：O571.6[理学—粒子物理与原子核物理]