Is the X(3872) a molecule?

Understand

Because of the controversial X(3872) meson's very close proximity to the $D^0\bar{D}^{*0}$ threshold, this charmonium-like resonance is often considered a meson-meson molecule.

• However, a molecular wave function must be essentially of a meson-meson type, viz.
• $D^0\bar{D}^{*0}$ in this case, with no other significant components.
• We address this issue by employing a simple two-channel Schr\"odinger model, in which the $J^{PC}=1^{++}$ $c\bar{c}$ and $D^0\bar{D}^{*0}$ channels can communicate via the $^3P_0$ mechanism, mimicked by string breaking at a sharp distance $a$.