Hunting for the $X_b$ via hidden bottomonium decays

Understand

In this work, we study the isospin conserved hidden bottomonium decay of $X_b\to \Upsilon(1S)\omega$, where $X_b$ is taken to be the counterpart of the famous $X(3872)$ in the bottomonium sector as a candidate for the meson-meson molecule.

• Since it is likely that the $X_b$ is below the $B\bar B^*$ threshold and the mass difference between the neutral and charged bottom meson is small compared to the binding energy of the $X_b$, the isospin violating decay mode $X_b\to \Upsilon (nS)\pi^+\pi^-$ would be greatly suppressed.
• We use the effective Lagrangian based on the heavy quark symmetry to explore the rescattering mechanism of $X_b\to \Upsilon(1S)\omega$ and calculate the partial widths.
• Our results show that the partial width for the $X_b\to \Upsilon(1S)\omega$ is about tens of keVs.