Ramos A, Oset E, Bennhold C
Departament d'Estructura i Constituents de la Matèria, Universitat de Barcelona, Diagonal 647, Spain.
Phys Rev Lett. 2002 Dec 16;89(25):252001. doi: 10.1103/PhysRevLett.89.252001. Epub 2002 Dec 2.
Using a unitary extension of chiral perturbation theory with a lowest-order s-wave SU(3) chiral Lagrangian we study low-energy meson-baryon scattering in the strangeness S=-2 sector. A scattering-matrix pole is found around 1605 MeV which corresponds to an s-wave Xi resonance with J(P)=1/2(-). We identify this resonance with the Xi(1620) state, quoted by the Particle Data Group with I=1/2 but with unknown spin and parity. The addition of the S=-2 state to the recently computed Lambda(1670), Sigma(1620), and N(1535) states completes the octet of J(P)=1/2(-) resonances dynamically generated in this chiral unitary approach.
利用具有最低阶 s 波 SU(3)手征拉格朗日量的手征微扰理论的幺正扩展，我们研究了奇异数 S = -2 扇区中的低能介子-重子散射。在 1605 MeV 附近发现了一个散射矩阵极点，它对应于一个 J(P)=1/2(-)的 s 波 Ξ 共振态。我们将这个共振态与粒子数据组引用的 Ξ(1620)态相识别，该态的同位旋 I = 1/2，但自旋和宇称未知。将 S = -2 态添加到最近计算出的 Λ(1670)、Σ(1620)和 N(1535)态中，完成了在这种手征幺正方法中动态产生的 J(P)=1/2(-)共振态的八重态。
