We present a search for the decay B+→τ+ν using 467.8×106 BBbar 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+ννbar, τ+→μ+ννbar, τ+→π+νbar and τ+→ρ+νbar. 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+0.53−0.49(stat)±0.24(syst))×10−4.

Evidence of B+→τ+ν decays with hadronic B tags

CONTRI, ROBERTO;GUIDO, ELISA;LO VETERE, MAURIZIO;MONGE, MARIA ROBERTA;ROBUTTI, ENRICO;
2013-01-01

Abstract

We present a search for the decay B+→τ+ν using 467.8×106 BBbar 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+ννbar, τ+→μ+ννbar, τ+→π+νbar and τ+→ρ+νbar. 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+0.53−0.49(stat)±0.24(syst))×10−4.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/696057
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