First search for the flavor changing neutral current decay D0 → γγ

Using 13.8 fb - 1 of data collected at or just below the Y(4S) with the CLEO detector, we report the result of a search for the flavor changing neutral current process D 0 → γγ. We observe no significant signal for this decay mode and determine 90% confidence level upper limits on the branching fractions B(D 0 → γγ)/B(D 0 → π 0 π 0 ) < 0.033 and B(D 0 → yy) < 2.9 X 10 - 5 .