We report the first observation of the decay J/psi --> 3 gamma. The signal has a statistical significance of 6 sigma and corresponds to a branching fraction of B(J/psi --> 3 gamma) = (1.2 +- 0.3 +- 0.2) x 10^-5, in which the errors are statistical and systematic, respectively. The measurement uses psi(2S) --> pi+ pi- J/psi events acquired with the CLEO-c detector operating at the CESR e+e- collider.
@article{arxiv.0806.0671,
title = {Observation of J/psi --> 3 gamma},
author = {CLEO Collaboration and G. S. Adams},
journal= {arXiv preprint arXiv:0806.0671},
year = {2010}
}
Comments
11 pages, available through http://www.lns.cornell.edu/public/CLNS/, submitted to PRL