Abstract

Out of 3.9 million hadronic Z decays collected by the ALEPH detector, a sample of approximately 700 J/ψ events decaying into e+ e- or μ+μ- are selected. A search for the Bc meson decaying into the channels J/ψπ+, J/ψe+νe and J/ψμ+νμ is then performed, resulting in the observation of 0, 1 and 1 candidate in each of these channels respectively, with 0.37, 0.28 and 0.36 background events expected. The following 90% confidence level upper limits are derived: [Formula: see text] An intriguing candidate, found in an independent analysis, is also described in detail. Using the same data sample, a search is performed for the ϒ(1S), ϒ(2S) and ϒ(3S) states, decaying into either e+e- or μ+μ-. After kinematic and topological cuts a total of 1.2 ± 0.4 background events are expected for both channels in the mass window chosen. Two events are observed, allowing the following 90% confidence level branching fraction upper limit to be derived: [Formula: see text]

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