We present searches for the leptonic decays B + → ℓ+nu and the lepton flavor violating decays B0 → ℓ+/-tau ∓, where ℓ = e, mu, with data collected by the BABAR experiment at SLAC. These searches utilize a technique in which we fully reconstruct the accompanying B¯ in Upsilon(4S) → BB¯ events, and look for a monoenergetic lepton in the signal B frame. The signal yield in the data is extracted from a fit to the signal lepton candidate momentum distribution in the signal B rest frame. Using a data sample of approximately 378 million BB¯ pairs (342 fb-1), we find no evidence of signal in any of the decay modes. Branching fraction upper limits of B (B+ → e +nu) < 5.2 x 10-6, B (B+ → mu+nu) < 5.6 x 10-6, B (B0 → e +tau-) < 2.8 x 10-5 and B (B0 → mu+tau -) < 2.2 x 10-5, are obtained at the 90% confidence level.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.112525 |
| Date | January 2007 |
| Creators | Klemetti, Miika A. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Physics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 002712108, proquestno: AAIMR51293, Theses scanned by UMI/ProQuest. |
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