Preliminary Results For Exclusive B->Ulv Decays From Cleo

A preliminary analysis of exclusive b --> ulv decays to the final states pi(-/+)l(+/-), pi(0+/-)v, rho-/+l+/-, rho(0)l(+/-)v and wl(+/-)b based on 2.2 x 10(6) decays collected at CLEO is presented. We have measured the first exclusive b --> ulv branching fraction B(B-0 --> pi(-)l(+)v) = [1.19 +/- 0.41 +/- 0.21 +/- 0.19] x 10(-4) ([1.70 +/- 0.51 +/- 0.31 +/- 0.27] x 10(-4)), with the ISGW (WSB) model used for efficiency determination. A 90% C.L. upper limit on B(B-0 --> rho(-)l(+)v) < 3.4 at the 90% confidence level for both the ISGW and WSB models. This ratio provides some discrimination between form factor models.