Observation of J/{psi}{yields}3{gamma}

We report the first observation of the decay J/{psi}{yields}3{gamma}. The signal has a statistical significance of 6{sigma} and corresponds to a branching fraction of B(J/{psi}{yields}3{gamma})=(1.2{+-}0.3{+-}0.2)x10{sup -5}, in which the errors are statistical and systematic, respectively. The measurement uses {psi}(2S){yields}{pi}{sup +}{pi}{sup -}J/{psi} events acquired with the CLEO-c detector operating at the CESR e{sup +}e{sup -} collider.