Ammar, Raymond G.Ball, S.Baringer, Philip S.Coppage, DonCopty, N.Davis, Robin E. P.Hancock, N.Kelly, M.Kwak, NowhanLam, H.2007-04-142007-04-141993-12BARTELT, J, CSORNA, SE, et al. Measurement of charmless semileptonic decays of B mesons. PHYSICAL REVIEW LETTERS. December 1993. 71(25) : 4111-4115https://hdl.handle.net/1808/1469Using the CLEO II detector and a sample of 955 000 UPSILON(4S) decays we have confirmed charmless semileptonic decays of B mesons. In the momentum interval 2.3-2.6 GeV/c we observe an excess of 107 +/- 15 +/- 11 leptons, which we attribute to b --> ulnu. This result yields a model-dependent range of values for \V(ub)/V(cb)\ that is lower than has been obtained in previous studies. For the inclusive spectator model of Altarelli et al. we find \V(ub)/V(cb)\ = 0.076 +/- 0.008. Models that describe b --> ulnu with a limited set of exclusive final states give \V(ub)/V(cb)\ = 0.06 - 0.10.en-USArticle10.1103/PhysRevLett.71.4111openAccess