Search $B_{c}$ and upsilon in hadronic Z decays

Out of 3.9 million hadronic Z decays collected by the ALEPH detector, a sample of approximately 800 Jj'lj; events decaying into e+e- orμ+μ- are selected. A search for the Be meson decaying into the channels J /'!/Y e+ve and J /'!jJμ+vμ is then performed, resulting in the observation of 1 candidate in each channel, with 0.28 and 0.37 back- ground events expected. The following 90% confidence level upper limit is derived: Using the same data sample, a search is performed for the Y(lS), Y(2S) and Y(3S) states, decaying into either e+e- or μ+ μ-. After kinematic and topological cuts a total of 1.0 ± 0.3 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: Br(Z -+ YX) < 9.9 x 10- 5 •