2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/165844We search for the purely leptonic decay $B^{\pm} \to μ^{\pm} ν_μ$ in the full BaBar dataset, having an integrated luminosity of approximately 426 fb$^{-1}$. We adopt a fully inclusive approach, where the signal candidate is identified by the highest momentum lepton in the event and the companion $B$ is inclusively reconstructed without trying to identify its decay products. We set a preliminary upper limit on the branching fraction of $\BR(B^{\pm} \to μ^{\pm} ν_μ) < 1.3 \times 10^{-6}$ at the 90% confidence level, using a Bayesian approach.10 pages, 8 postscript figures, submitted to ICHEP2008High Energy Physics - Experimenttext