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Evidence for B Semileptonic Decays into the Lambda_c Charm Baryon

Description: We present the first evidence for B semileptonic decays into the charmed baryon {Lambda}{sub c}{sup +} based on 420 fb{sup -1} of data collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} storage rings. Events are tagged by fully reconstructing one of the B mesons in a hadronic decay mode. We measure the relative branching fraction {Beta}({bar B} {yields} {Lambda}{sub c}{sup +} X{ell}{sup -}{bar {nu}}{sub {ell}})/{Beta}({bar B} {yields} {Lambda}{sub c}{sup +}/{bar {Lambda}}{sub c}{sup -}X) = (3.2 {+-} 0.9{sub stat.} {+-} 0.9{sub syst.})%. The significance of the signal including the systematic uncertainty is 4.9 standard deviations.
Date: November 5, 2008
Creator: Aubert, Bernard; Bona, M.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the Branching Fractions of Bbar -> D** l^- nubar_l Decays in Events Tagged by a Fully Reconstructed B Meson

Description: We report a measurement of the branching fractions of {bar B} {yields} D** {ell}{sup -}{bar {nu}}{sub {ell}} decays based on 417 fb{sup -1} of data collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} storage rings. Events are selected by fully reconstructing one of the B mesons in a hadronic decay mode. A fit to the invariant mass differences m(D{sup (*)})-m(D{sup (*)}) is performed to extract the signal yields of the different D** states. We observe the {bar B} {yields} D**{ell}{sup -}{bar {nu}}{sub {ell}} decay modes corresponding to the four D** states predicted by Heavy Quark Symmetry with a significance greater than six standard deviations including systematic uncertainties.
Date: November 5, 2008
Creator: Aubert, Bernard; Bona, M.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E. et al.
Partner: UNT Libraries Government Documents Department