New Measurement of {ital B} {r_arrow} {ital D}{sup {asterisk}}{ital {pi}} Branching Fractions

The decays {Upsilon}(4S){r_arrow}B{ovr B} , followed by B{r_arrow}D{sup {asterisk}}{pi} and D{sup {asterisk}}{r_arrow}D{pi} , permit reconstruction of all kinematic quantities that describe the sequence without reconstruction of the D , with reasonably low backgrounds. Using an integrated e{sup +}e{sup {minus}} luminosity of 3.1 fb{sup {minus}1} accumulated at the {Upsilon}(4S) by the CLEO-II detector, we report measurements of B({ovr B}{sup 0}{r_arrow} D{sup {asterisk}+}{pi}{sup {minus}})=(2.81{plus_minus} 0.11{plus_minus}0.21{plus_minus}0.05){times}10{sup {minus}3} and B(B{sup {minus}}{r_arrow}D{sup {asterisk}0}{pi}{sup {minus}})=(4.34{plus_minus}0.33{plus_minus}0.34{plus_minus}0.1 8){times}10{sup {minus}3} . {copyright} {ital 1998} {ital The American Physical Society}