Abstract
We report on the observation of the , the radial excitation of the ground state of charmonium, in the two-photon fusion reaction in of CLEO II/II.V data and of CLEO III data. We obtain and . The corresponding values of hyperfine splittings between and states are and . Assuming that the and have equal branching fractions to , we obtain .
- Received 23 December 2003
DOI:https://doi.org/10.1103/PhysRevLett.92.142001
©2004 American Physical Society