Study of Bs Oscillations using Inclusive Lepton Events
Abstract
A search for Bs oscillations is performed using a sample of semileptonic b-hadron decays collected by the ALEPH experiment during 1991-1995. The current work improves upon the corresponding published ALEPH analysis, which has the highest sensitivity, to date. A larger sample is studied, using loose selection criteria and improved lepton identification. The probability that a lepton candidate originates from the direct decay of a Bs meson is estimated, on an event-by-event basis, by studying several exclusive and topological properties of the event, combined by meand of neural networks. The same technique is used to merge variables which carry information about the nature of the b-particle at production time, into one single initial state tagging variable. Finally, a new vertexing algorithm is developed which yields an improved decay length resolution on a wider sample of events. For the first time, photons are successfully used to achieve the ultimate precision in the inclusive reconstruction of the b vertex position. Particular care is taken to assign an accurate event-by-event uncertainty to the reconstructed b decay length. The new developments altogether yield a major improvement in the statistical power of the analysis compared to the published result.
- Publication:
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APS April Meeting Abstracts
- Pub Date:
- April 2000
- Bibcode:
- 2000APS..APRV15009B