The possible interpretations of Y(4260)

Shi-Lin Zhu
2005 Physics Letters B  
The recently observed Y(4260) lies far above the decay threshold with a width less than 100 MeV. We argue that it's very difficult to accommodate Y(4260) as a conventional cc̅ radial excitation or a D-wave state. It can't be a hadronic molecule. Its production mechanism and special decay pattern do not favor the glueball interpretation. If Y(4260) is a scalar tetraquark, it must be produced by the I=0 component of the virtual photon. Then the I=1, I_z=0 component of the virtual photon should
more » ... e produced its isovector partner Y^' (4260), which may be searched for in the decay channel π^+π^-π^0 J/ψ using exactly the same database from the initial state radiation process. The observation/non-observation of Y^' (4260) can easily confirm/reject the tetraquark hypothesis. However, a tetraquark far above threshold can fall apart into DD̅, D^∗D̅ very easily. Its not-so-large width and the non-observation of DD̅ mode tend to disfavor the tetraquark hypothesis. Hence the only feasible interpretation is a hybrid charmonium if Y(4260) is NOT an experimental artifact. At present, none of the experimental information from BABAR measurement is in conflict with the hybrid charmonium picture.
doi:10.1016/j.physletb.2005.08.068 fatcat:zvgb6zkhnret5ep5rkwyvwyrfe