We present a search for the decay B+→τ+ν using 467.8×106 BB¯ pairs collected at the Υ(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. We select a sample of events with one completely reconstructed B- in the hadronic decay mode (B-→D(*)0X- and B-→J/ψX-). We examine the rest of the event to search for a B+→τ+ν decay. We identify the τ+ lepton in the following modes: τ+→e+νν¯, τ+→μ+νν¯, τ+→π+ν¯ and τ+→ρ+ν¯. We find an excess of events with respect to the expected background, which excludes the null signal hypothesis at the level of 3.8σ (including systematic uncertainties) and corresponds to a branching fraction value of B(B+→τ+ν)=(1.83-0.49+0.53(stat)±0.24(syst))×10-4.

Evidence of B^{+}→τ^{+}ν decays with hadronic B tags

LANCERI, LIVIO;VITALE, LORENZO;
2013

Abstract

We present a search for the decay B+→τ+ν using 467.8×106 BB¯ pairs collected at the Υ(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. We select a sample of events with one completely reconstructed B- in the hadronic decay mode (B-→D(*)0X- and B-→J/ψX-). We examine the rest of the event to search for a B+→τ+ν decay. We identify the τ+ lepton in the following modes: τ+→e+νν¯, τ+→μ+νν¯, τ+→π+ν¯ and τ+→ρ+ν¯. We find an excess of events with respect to the expected background, which excludes the null signal hypothesis at the level of 3.8σ (including systematic uncertainties) and corresponds to a branching fraction value of B(B+→τ+ν)=(1.83-0.49+0.53(stat)±0.24(syst))×10-4.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11368/2768949
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