2 research outputs found

    Search for the bcb_c meson in hadronic Z decays

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    A search for the Bc meson decaying into the channels J/psi pi+ and J/psi l nu (l = e or mu) is performed in a sample of 3.9 million hadronic Z decays collected by the ALEPH detector. This search results in the observation of 0 and 2 candidates in each of these channels, respectively, while 0.44 and 0.81 background events are expected. The following 90\% confidence level upper limits are derived: Br(Z->Bc X)/Br(Z->q q )*Br(Bc->J/psi pi+) 3.6 10^-5 Br(Z->Bc X)/Br(Z->q q )*Br(Bc->J/psi l nu) 5.2 10^-5 An additional Bc->J/psi(e+e-) mu nu candidate with very low background probability, found in an independent analysis, is also described in detail

    Measurement of the branching fraction for d0Kπ+d^0 \rightarrow K^-\pi^+

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    The branching fraction for D0 -> K- pi+ is measured with the statistics collected by ALEPH from 1991 to 1994. The method is based on the comparison between the rate for the reconstructed D*+ -> D0 pi+, D0 -> K- pi+ decay chain and the rate for inclusive soft pion production at low transverse momentum with respect to the nearest jet. The result found is B(D0 -> K- pi+) = (3.90 +- 0.09 +- 0.12)
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