Measurement of B(D{sup 0} {r_arrow} K{sup {minus}}{pi}{sup +}) Using Partial Reconstruction of {ovr B} {r_arrow} D{sup *+}Xscr(l){sup {minus}}{bar {nu}}

We present a measurement of the absolute branching fraction for D{sup 0}{r_arrow}K{sup {minus}}{pi}{sup +} using the reconstruction of the decay chain {ovr B}{r_arrow}D{sup *+}X{ell}{sup {minus}}{ovr {nu} } , D{sup *+}{r_arrow}D{sup 0}{pi}{sup +} where only the lepton and the low-momentum pion from the D{sup *+} are detected. With data collected by the CLEO II detector at the Cornell Electron Storage Ring, we have determined B(D{sup 0}{r_arrow}K{sup {minus}}{pi}{sup +})=[3.81{plus_minus}0.15(stat) {plus_minus}0.16(syst)]{percent} . {copyright} {ital 1998} {ital The American Physical Society}