Is the newly reported $X(5568)$ a $B\bar{K}$ molecular state?

TL;DR

This study analyzes the potential for $B^{(*)}ar{K}$ molecular states and concludes that the reported $X(5568)$ is unlikely to be such a state, while predicting new isoscalar molecular states for future exploration.

Contribution

The paper provides a dynamical analysis showing the $X(5568)$ is not a $Bar{K}$ molecule and predicts new isoscalar $B^{(*)}ar{K}$ molecular states.

Findings

$X(5568)$ cannot be an isovector $Bar{K}$ or $B^*ar{K}$ molecular state.

Predicted existence of several isoscalar $B^{(*)}ar K^{(*)}$ molecular states.

Future experiments should explore open-bottom molecular states.

Abstract

In this work, we perform a dynamical study of the $B^{(*)}$ and $\bar K$ interaction and show that the newly reported $X(5568)$ or $X(5616)$ cannot be assigned to be an isovector $B\bar{K}$ or $B^*\bar{K}$ molecular state. We continue to investigate the isoscalar $B^{(*)}\bar{K}$ systems, and the $B^{(*)}\bar{K}$ systems with isospin $I=0,1$, and predict the existence of several isoscalar $B^{(*)}\bar K^{(*)}$ molecular states. A new task of exploring open-bottom molecular states will be created for future experiments.