Measurement of the ratio B(D0'e)B(D0K-e+e)

Using the CLEO detector at the Cornell Electron Storage Ring, we have performed a direct measurement of the ratio of D0 semileptonic branching fractions into vector and pseudoscalar final states. We find B(D0K*-e+e)B(D0K-e+e)=0.510.180.06, in agreement with the ratio derived by the E691 experiment which compares D+ and D0 final states. We also set an upper limit on the ratio B(D0*0-e+e)B(D0K*-e+e)<0.64 at 90% confidence level. © 1991 The American Physical Society.