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ISSN - 00319007, EISSN - 10797114, Physical Review Letters, 2007, vol. 98, p. -

Measurement of the B0→π-l+ν form-factor shape and branching fraction, and determination of |Vub| with a loose neutrino reconstruction technique

Aubert B., Bona M., Boutigny D., Karyotakis Y., Lees J. P., Poireau V., Prudent X., Tisserand V., Zghiche A., Grauges E., Palano A., Chen J. C., Qi N. D., Rong G., Wang P., Zhu Y. S., Eigen G., Ofte I., Stugu B., Abrams G. S., Battaglia M., Brown D. N., Button-Shafer J., Cahn R. N., Groysman Y., Jacobsen R. G., Kadyk J. A., Kerth L. T., Kolomensky Yu G., Kukartsev G., Lopes Pegna D., Lynch G., Mir L. M., Orimoto T. J., Pripstein M., Roe N. A., Ronan M. T., Tackmann K., Wenzel W. A., Del Amo Sanchez P., Barrett M., Harrison T. J., Hart A. J., Hawkes C. M., Watson A. T., Held T., Koch H., Lewandowski B., Pelizaeus M., Peters K., Schroeder T., Steinke M., Boyd J. T., Burke J. P., Cottingham W. N., Walker D., Asgeirsson D. J., Cuhadar-Donszelmann T., Fulsom B. G., Hearty C., Knecht N. S., Mattison T. S., McKenna J. A., Khan A., Kyberd P., Saleem M., Sherwood D. J., Teodorescu L., Blinov V. E., Bukin A. D., Druzhinin V. P., Golubev V. B., Onuchin A. P., Serednyakov S. I., Skovpen Yu I., Solodov E. P., Todyshev K. Yu, Bondioli M., Bruinsma M., Chao M., Curry S., Eschrich I., Kirkby D., Lankford A. J., Lund P., Mandelkern M., Martin E. C., Stoker D. P., Abachi S., Buchanan C., Foulkes S. D., Gary J. W., Liu F., Long O., Shen B. C., Zhang L., Hill E. J., Paar H. P., Rahatlou S., Sharma V.

We report the results of a study of the exclusive charmless semileptonic decay, B0→π-ℓ+ν, undertaken with approximately 227×106 BB̄ pairs collected at the Υ(4S) resonance with the BABAR detector. The analysis uses events in which the signal B decays are reconstructed with an innovative loose neutrino reconstruction technique. We obtain partial branching fractions in 12 bins of q2, the momentum transfer squared, from which we extract the f+(q2) form-factor shape and the total branching fraction B(B0→π-ℓ+ν)=(1.46±0.07stat±0.08syst)×10-4. Based on a recent unquenched lattice QCD calculation of the form factor in the range q2>16GeV2, we find the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element |Vub| to be (4.1±0.2stat±0.2syst+0.6-0.4FF) ×10-3, where the last uncertainty is due to the normalization of the form factor. © 2007 The American Physical Society.