Exclusive Semileptonic b->u l nu Decays at CLEO

Abstract

Updated CLEO results are presented for branching ratios and four-momentum transfer q^2 dependence of exclusive charmless semileptonic B decays, where the final state hadron is either a pi, rho, omega, eta or eta'. These results have comparable accuracies with those of other experiments. We address the issue of flavor singlet couplings by limiting Gamma(B+ -> eta' l+ nu)/\Gamma(B+ -> eta l+ nu)> 2.5 at 90 % CL}. We also extract a value of |V_{ub}|= (4.3 +/- 0.4 +/-0.2^{+0.6}_{-0.4})x10^{-3} in one particular unquenched lattice QCD model using pi l+nu data above q^2 of 16 GeV^2.