Communications in Theoretical Physics ›› 2022, Vol. 74 ›› Issue (7): 075201. doi: 10.1088/1572-9494/ac738a

• Particle Physics and Quantum Field Theory • Previous Articles     Next Articles

The pseudoscalar meson and baryon octet interaction with strangeness S = −2 in the unitary coupled-channel approximation

Bao-Xi Sun(), Xin-Yu Liu()   

  1. Faculty of Science, Beijing University of Technology, Beijing 100124, China
  • Received: 2022-03-09 Revised: 2022-05-17 Accepted: 2022-05-26 Published: 2022-07-01
  • Contact: Xin-Yu Liu E-mail:sunbx@bjut.edu.cn;liuxinyu@emails.bjut.edu.cn

Abstract:

The interaction of the pseudoscalar meson and the baryon octet with strangeness $S=-2$ and isospin $I=1/2$ is investigated by solving the Bethe–Salpeter equation in the infinite and finite volume respectively. It is found that there is a resonance state generated dynamically, which owns a mass of about 1550 MeV and a large decay width of 120–200 MeV. This resonance state couples strongly to the π${\rm{\Xi }}$ channel. Therefore, it might not correspond to the ${\rm{\Xi }}(1620)$ particle announced by Belle collaboration. At the same time, this problem is studied in the finite volume, and an energy level at 1570 MeV is obtained, which is between the ${\pi }{\rm{\Xi }}$ and $\bar{K}{\rm{\Lambda }}$ thresholds and independent of the cubic box size.

Key words: Bethe–Salpeter equation, chiral unitary approach, amplitude