Extracting |V(ub)| from B->pi l nu Decays Using a Multiply-subtracted Omnes Dispersion Relation

We use a multiply-subtracted Omnes dispersion relation for the form factor f^+ in B->pi semileptonic decay, allowing the direct input of experimental and theoretical information to constrain its dependence on q^2. Apart from these inputs we use only unitarity and analyticity properties. We obtain |V(ub)|=(4.00 \pm 0.36)\times 10^{-3}