$Z_b(10610)^\pm$ and $Z_b(10650)^\pm$ as the $B^*\bar{B}$ and $B^*\bar{B}^{*}$ molecular states

TL;DR

This paper uses the one-boson-exchange model to interpret the $Z_b(10610)$ and $Z_b(10650)$ as molecular states of $B^*ar{B}$ and $B^*ar{B}^*$, supporting their molecular nature with robust long-range force calculations.

Contribution

It provides a natural interpretation of the $Z_b$ states as molecular states and predicts related molecular bottomonia and charmonia within the same framework.

Findings

$Z_b(10610)$ and $Z_b(10650)$ are likely $B^*ar{B}$ and $B^*ar{B}^*$ molecular states.

Long-range one-pion-exchange force can form these loosely bound states.

The model predicts additional molecular bottomonia and charmonia.

Abstract

In the framework of the one-boson-exchange model, we have studied the interaction of the $B^*\bar{B}$ and $B^*\bar{B}^{*}$ system. After considering the S-wave and D-wave mixing, we notice that both $Z_b(10610)^\pm$ and $Z_b(10650)^\pm$ can be interpreted as the $B^*\bar{B}$ and $B^*\bar{B}^{*}$ molecular states quite naturally. Within the same framework, there also exist several molecular charmonia including X(3872) and several other molecular bottomonia, which are the partners of $Z_b(10610)$ and $Z_b(10650)$. The long-range one-pion-exchange force alone is strong enough to form these loosely bound molecular states, which ensures the numerical results quite model-independent and robust.