Hidden charm dynamically generated resonances and the e+e- → J/ψD(D)over-bar, J/ψD(D)over-bar* reactions

We analyze two recent reactions of Belle, producing D (D) over bar and D (D) over bar* states that have an enhancement of the invariant D (D) over bar, D (D) over bar* mass distribution above threshold, from the point of view that they might be indicative of the existence of a hidden charm scalar and an axial vector meson state below D (D) over bar or D (D) over bar* thresholds, respectively. We conclude that the data is compatible with the existing prediction of a hidden charm scalar meson with mass around 3700MeV, though other possibilities cannot be discarded. The peak seen in the D (D) over bar* spectrum above threshold is, however, unlikely to be due to a threshold enhancement produced by the presence, below threshold, of the hidden charm axial vector meson X(3872).