Long-distance structure of the X(3872)

TL;DR

This paper explores the structure of the X(3872) as a hadronic molecule, predicts new related states using heavy quark symmetries, and analyzes the decay modes sensitive to its long-distance structure.

Contribution

It introduces predictions of new hadronic molecules based on heavy quark symmetries and studies the decay modes of X(3872) to probe its long-distance structure.

Findings

Predicted an isoscalar Bar B^* bound state around 10580 MeV.

Identified decay modes sensitive to the long-distance structure of X(3872).

Discussed the importance of D^0 ar D^0 final state interactions.

Abstract

We investigate heavy quark symmetries for heavy meson hadronic molecules, and explore the consequences of assuming the X(3872) and $Z_b(10610)$ as an isoscalar $D\bar D^*$ and an isovector $B\bar B^*$ hadronic molecules, respectively. The symmetry allows to predict new hadronic molecules, in particular we find an isoscalar $1^{++}$ $B\bar B^*$ bound state with a mass about 10580 MeV and the isovector charmonium partners of the $Z_b(10610)$ and the $Z_b(10650)$ states. Next, we study the $X(3872) \to D^0 \bar D^0\pi^0$ three body decay. This decay mode is more sensitive to the long-distance structure of the X(3872) resonance than its $J/\psi\pi\pi$ and $J/\psi3\pi$ decays, which are mainly controlled by the short distance part of the X(3872) molecular wave function. We discuss the $D^0 \bar D^0$ final state interactions, which in some situations become quite important. Indeed in these cases, a precise measurement of this partial decay width could provide precise information on the interaction strength between the $D^{(*)}\bar D^{(*)}$ charm mesons.