# Studying the Bound State of the $B\overline{K}$ System in the Bethe-Salpeter Formalism

Guo, Xin-Heng  (College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China) ; Wang, Zhen-Yang (Physics Department, Ningbo University, Zhejiang 315211, China) ; Qi, Jing-Juan (College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China)

04 March 2019

Abstract: In this work, we study the $B\overline{K}$ molecule in the Bethe-Salpeter (BS) equation approach. With the kernel containing one-particle-exchange diagrams and introducing two different form factors (monopole form factor and dipole form factor) in the vertex, we solve the BS equation numerically in the covariant instantaneous approximation. We investigate the isoscalar and isovector $B\overline{K}$ systems, and we find that $X\left(\mathrm{5568}\right)$ cannot be a $B\overline{K}$ molecule.

Published in: Advances in High Energy Physics 2019 (2019) 7576254