Long-distance structure of the X(3872)

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 $D{\bar{D}}^{\ast }$ and an isovector $B{\bar{B}}^{\ast }$ hadronic molecules, respectively. The symmetry allows to predict new hadronic molecules, in particular we find an isoscalar $1^{++}$ $B{\bar{B}}^{\ast }$ 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 $J/\psi 3\pi$ 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 $D^{(\ast )}{\bar{D}}^{(\ast )}$ charm mesons.

Comments: Talk presented at the "XI International Conference on Hyperons, Charm and Beauty Hadrons (BEACH 2014)", Birmingham (U.K.), July 2014