Abstract
The two-photon transition is studied in a sample of decays collected by the BESIII detector. The branching fraction is measured to be using and decays, and its upper limit is estimated to be at the confidence level. This work represents the first measurement of a two-photon transition among charmonium states. The orientation of the decay plane and the polarization in this decay are also studied. In addition, the product branching fractions of sequential transitions and are reported.
- Received 1 April 2012
DOI:https://doi.org/10.1103/PhysRevLett.109.172002
© 2012 American Physical Society