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  • Measurement of the [formula...
    Abreu, P.; Almehed, S.; Andreazza, A.; Arnoud, Y.; Augustin, J-E.; Barbier, R.; Battaglia, M.; Baubillier, M.; Berggren, M.; Bertrand, D.; Borisov, G.; Bosio, C.; Boudinov, E.; Buschbeck, B.; Camporesi, T.; Canale, V.; Carena, F.; Cattai, A.; Chelkov, G.A.; Chorowicz, V.; Crawley, H.B.; Crepe, S.; Da Silva, W.; De Boer, W.; De Paula, L.; Drees, J.; Eigen, G.; Elsing, M.; Engel, J-P.; Espirito Santo, M.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Ferrari, P.; Ferro, F.; Fichet, S.; Foeth, H.; Franek, B.; Fruhwirth, R.; Fuster, J.; Gerdyukov, L.; Gonzalez Caballero, I.; Gopal, G.; Gris, P.; Grosdidier, G.; Guy, J.; Herquet, P.; Holmgren, S-O.; Holt, P.J.; Houlden, M.; Huet, K.; Jalocha, P.; Keranen, R.; Khokhlov, Yu; Lauhakangas, R.; Lemonne, J.; Liko, D.; Loerstad, B.; Lutz, P.; Marco, J.; Marechal, B.; Margoni, M.; Martinez-Vidal, F.; Matthiae, G.; Mazzucato, F.; Miagkov, A.; Mjoernmark, U.; Mulet-Marquis, C.; Myklebust, T.; Navarria, F.L.; Navas, S.; Olshevski, A.G.; Ouraou, A.; Parkes, C.; Passeri, A.; Pernicka, M.; Phillips, H.T.; Podobnik, T.; Privitera, P.; Regler, M.; Renton, P.B.; Romero, A.; Ronchese, P.; Ruhlmann-Kleider, V.; Sampsonidis, D.; Schwemling, Ph; Sekulin, R.; Squarcia, S.; Stevenson, K.; Stocchi, A.; Taffard, A.; Tonazzo, A.; Tortora, L.; Tristram, G.; Trochimczuk, M.; Vrba, V.; Wahlen, H.; Washbrook, A.J.; Yushchenko, O.; Zoller, Ph

    Physics letters. B, 3/2000, Letnik: 475, Številka: 3
    Journal Article

    A study of b semileptonic decays into D, Dπ ± and D ∗π ± final states is presented. The D 0, D + and D ∗+ mesons are exclusively reconstructed in Z decay data recorded from 1992 to 1995 in the DELPHI experiment at LEP. The overall branching fractions are measured to be: BR(b→D 0ℓ − ν ̄ ℓX)=(7.04±0.34 (stat)±0.36 (syst.exp)±0.17 ( BR D))% , BR(b→D +ℓ − ν ̄ ℓX)=(2.72±0.19 (stat)±0.16 (syst.exp)±0.18 ( BR D))% , BR(b→D ∗+ℓ − ν ̄ ℓX)=(2.75±0.17 (stat)±0.13 (syst.exp)±0.09 ( BR D))% , where the D 0 and D + results include also contributions from D ∗0 and D ∗+ decays. A fit to the distribution of the π ± impact parameter to the primary interaction vertex provides a measurement of the b semileptonic branching fractions into the D 0 π ± X, D + π ± X and D ∗+π ±X final states. Assuming that single pion decay modes of B mesons dominate, the partial rates for B ̄ →Dπℓ − ν ℓ ̄ and B ̄ →D ∗πℓ − ν ℓ ̄ have been obtained, corresponding to a total branching fraction: BR( B ̄ →Dπℓ − ν ℓ ̄ )+ BR( B ̄ →D ∗πℓ − ν ℓ ̄ )=(3.40±0.52 (stat)±0.32 (syst))% . This result agrees well with the observed difference between the total B semileptonic branching fraction and the sum of the B ̄ →Dℓ − ν ℓ ̄ and D ∗ℓ − ν ℓ ̄ branching fractions.