Abstract The X (3872) is theoretically predicted to have a spin-0 partner state denoted as X 0 . Assuming the X 0 as a D D molecular bound state, we calculate the decay widths of X 0 → VV and X 0 → PP ( V and P stand for light vector and pseudoscalar mesons, respectively) via intermediate charmed meson loops. Three different configurations of the X 0 , i.e., pure neutral components ( θ = 0), isospin singlet ( θ = π /4) and pure charged components ( θ = π /2), are investigated. Within a commonly accepted range of the model parameter α , the predicted decay widths of X 0 → VV are on the order of a few hundred keV, while the decay widths of X 0 → PP can reach several MeV. The X 0 → ρρ and ππ have larger decay rates. The relative width ratios between the channels are nearly model-independent. Moreover, among those channels only with isovector or isoscalar mesons, the relevant ratios are also independent of the phase angle. The predicted ratios are helpful for searching the X 0 in the future experiments at BESIII and Belle II.
Gao et al. (Mon,) studied this question.