Evidence of B[superscript +]→τ[superscript +]ν decays with hadronic B tags

• Main Authors: Cowan, Ray Franklin (Contributor), Dujmic, D. (Contributor), Sciolla, Gabriella (Contributor)
• Other Authors: Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2013-10-15T16:52:01Z.
• Subjects: Article
• Online Access: Get fulltext

 We present a search for the decay B[superscript +]→τ[superscript +]ν using 467.8×10[superscript 6] BB̅ 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[superscript -] in the hadronic decay mode (B[superscript -]→D[superscript (*)0]X[superscript -] and B[superscript -]→J/ψX[superscript -]). We examine the rest of the event to search for a B[superscript +]→τ[superscript +]ν decay. We identify the τ[superscript +] lepton in the following modes: τ[superscript +]→e[superscript +]νν̅ , τ[superscript +]→μ[superscript +]νν̅ , τ[superscript +]→π[superscript +]ν̅ and τ[superscript +]→ρ[superscript +]ν̅ . 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[superscript +]→τ[superscript +]ν)=(1.83[+0.53 over -0.49](stat)±0.24(syst))×10[superscript -4].