First Search for the Flavor Changing Neutral Current Decay D^0 -> gamma gamma

Abstract

Using 13.8 fb^{-1} of data collected at or just below the Υ(4S) with the CLEO detector, we report the result of a search for the flavor changing neutral current process D^{0} \to γγ. We observe no significant signal for this decay mode and determine 90% confidence level upper limits on the branching fractions Br(D^{0}\to γγ)/Br(D^{0}\toπ^{0}π^{0}) < 0.033 and Br(D^{0}\toγγ) < 2.9 \times 10^{-5}.''

6 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, submitted to PRL