# $$B_s\pi$$ – $$B\bar{K}$$ interactions in finite volume and X(5568)

The European Physical Journal C, Feb 2017

The recent observation of X(5568) by the D0 Collaboration has aroused a lot of interest both theoretically and experimentally. In the present work, we first point out that X(5568) and $$D_{s0}^*(2317)$$ cannot simultaneously be of molecular nature, from the perspective of heavy-quark symmetry and chiral symmetry, based on a previous study of the lattice QCD scattering lengths of DK and its coupled channels. Then we compute the discrete energy levels of the $$B_s\pi$$ and $$B\bar{K}$$ system in finite volume using unitary chiral perturbation theory. The comparison with the latest lattice QCD simulation, which disfavors the existence of X(5568), supports our picture where the $$B_s\pi$$ and $$B\bar{K}$$ interactions are weak and X(5568) cannot be a $$B_s\pi$$ and $$B\bar{K}$$ molecular state. In addition, we show that the extended Weinberg compositeness condition also indicates that X(5568) cannot be a molecular state made from $$B_s\pi$$ and $$B\bar{K}$$ interactions.

This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1140%2Fepjc%2Fs10052-017-4660-9.pdf

Jun-Xu Lu, Xiu-Lei Ren, Li-Sheng Geng. $$B_s\pi$$ – $$B\bar{K}$$ interactions in finite volume and X(5568), The European Physical Journal C, 2017, 94, DOI: 10.1140/epjc/s10052-017-4660-9