Measurement of V$_{cb}$ from the decay process $\bar{B^0}$ - D$^{+} \ell^- \bar{\nu}

• Published in: Physics letters. B 2001-04, Vol.510, p.55-74
• Main Authors: Abreu, P., Adam, W., Adye, T., Adzic, P., Albrecht, Z., Alderweireld, T., Alekseev, G.D., Alemany, R., Allmendinger, T., Allport, P.P., Almehed, S., Amaldi, U., Amapane, N., Amato, S., Anassontzis, E.G., Andersson, P., Andreazza, A., Andringa, S., Antilogus, P., Apel, W.D., Arnoud, Y., Asman, B., Augustin, J.-E., Augustinus, A., Baillon, P., Ballestrero, A., Bambade, P., Barao, F., Barbiellini, Guido, Barbier, R., Bardin, D.Y., Barker, G., Baroncelli, A., Battaglia, M., Baubillier, M., Becks, K.H., Begalli, M., Behrmann, A., Beilliere, P., Belokopytov, Yu, Belous, K., Benekos, N.C., Benvenuti, A.C., Berat, C., Berggren, M., Berntzon, L., Bertrand, D., Besancon, M., Bilenky, M.S., Bizouard, M.A., Bloch, D., Blom, H.M., Bonesini, M., Boonekamp, M., Booth, P.S.L., Borisov, G., Bosio, C., Botner, O., Boudinov, E., Bouquet, B., Bourdarios, C., Bowcock, T.J.V., Boyko, I., Bozovic, I., Bozzo, M., Bracko, M., Branchini, P., Brenner, R.A., Bruckman, P., Brunet, J.M., Bugge, L., Buran, T., Buschbeck, B., Buschmann, P., Cabrera, S., Caccia, M., Calvi, M., Camporesi, T., Canale, V., Carena, F., Carroll, L., Caso, C., Castillo Gimenez, M.V., Cattai, A., Cavallo, F.R., Chapkin, M., Charpentier, P., Checchia, P., Chelkov, G.A., Chierici, R., Chliapnikov, P., Chochula, P., Chorowicz, V., Chudoba, J., Cieslik, K., Collins, P., Contri, R., Cortina, E., Cosme, G., Cossutti, F.
• Format: Article
• Language: English
• Subjects: High Energy Physics - Experiment; Physics
• ISSN: 0370-2693
• DOI: 10.1016/S0370-2693(01)00569-X

A new precise measurement of |V_{cb}| and of the branching ratio BR(\bar{B^0} -> D^{*+} \ell^- \bar{\nu_\ell}) has been performed using a sample of about 5000 semileptonic decays \bar{B^0} -> D^{*+} \ell^- \bar{\nu_\ell}, selected by the DELPHI detector at LEP I by tagging the soft pion from D^{*+} -> D^0 \pi^+. The results are: V_{cb}=(39.0 +/- 1.5 (stat.) ^{+2.5}_{-2.6} (syst. exp.) +/- 1.3 (syst. th.)) x 10^{-3} BR(\bar{B^0} -> D^{*+} \ell^- \bar{\nu_\ell})=(4.70 +/- 0.13 (stat.) ^{+0.36} _{-0.31} (syst. exp.))% The analytic dependences of the differential cross-section and of the Isgur Wise form factor as functions of the variable w = v_{B^0}.v_{D^*} have also been obtained by unfolding the experimental resolution.