Exclusive Semileptonic b->u l nu Decays at CLEO

TL;DR

This paper presents updated measurements of exclusive semileptonic B decays to various hadrons, providing insights into branching ratios, q^2 dependence, flavor singlet couplings, and an extraction of |V_{ub}| using lattice QCD models.

Contribution

It offers new experimental results on branching ratios and q^2 dependence, and extracts |V_{ub}| using lattice QCD, improving understanding of semileptonic B decays.

Findings

Branching ratios comparable to other experiments.

Limit on flavor singlet coupling ratio > 2.5 at 90% CL.

|V_{ub}| measured as (4.3 +/- 0.4 +/- 0.2 +0.6/-0.4) x 10^{-3}.

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.