Upper limit for axion production in radiativeϒdecay

We have used the CUSB detector at the Cornell Electron Storage Ring to study the decays of Υ(1S) and Υ(3S) resonances into a single photon plus a long-lived noninteracting particle. We obtain an upper limit on the branching ratio for Υ(1S)→γ+X, where X is undetected. This upper limit is 3.5×{}10^-4 (90% C.L.) for masses mX less than 7 GeV. For the Υ(3S) the upper limit is 1.2×{}10^-4 (90% C.L.) for masses less than 4 GeV. Also, the product of the branching ratios of Υ→γ+axion and Jψ→γ+axion is calculated to be 0.6×{}10^-9, inconsistent with theoretical predictions.