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Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/131444

Search for B+ → τ+ν

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We present a search for the decay B + → τ + ν using 383 × 10 6 B ¯¯¯ B pairs collected at the Υ ( 4 S ) resonance with the BABAR detector at the SLAC PEP-II B -Factory. A sample of events with one reconstructed semileptonic B decay ( B − → D 0 ℓ − ¯ ν ℓ X ) is selected, and in the recoil a search for B + → τ + ν is performed. The τ is identified in the following channels: τ + → e + ν ¯ ν , τ + → μ + ν ¯ ν , τ + → π + ¯ ν , and τ + → π + π 0 ¯ ν . We measure a branching fraction of B ( B + → τ + ν ) = ( 0.9 ± 0.6 ( stat . ) ± 0.1 ( syst . ) ) × 10 − 4 . In the absence of a significant signal, we calculate an upper limit at the 90% confidence level of B ( B + → τ + ν ) < 1.7 × 10 − 4 . We calculate the product of the B meson decay constant f B and | V ub | to be f B ⋅ | V ub | = ( 7.2 + 2.0 − 2.8 ( stat . ) ± 0.2 ( syst . ) ) × 10 − 4     GeV .

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GARRA TICÓ, Jordi, GRAUGÉS POUS, Eugeni and BABAR Collaboration. Search for B+ → τ+ν. Physical Review D. 2007. Vol. 76, num. 5, pags. 052002. ISSN 1550-7998. [consulted: 12 of June of 2026]. Available at: https://hdl.handle.net/2445/131444

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