2008/10/18 by K. Hara, Hara, K.
Engineering · Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #Particle Accelerators and Free-Electron Lasers #Particle Detector Development and Performance #Particle physics theoretical and experimental studies
paper · pdf · doi:10.48550/arxiv.0810.3301
openalex publication_date 2008/10/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present a new measurement of the purely leptonic decay B- -> tau- nutau-bar with a semileptonic B tagging method, using a data sample containing 657*106 BB-bar pairs collected with the Belle detector at the KEKB asymmetric e+e- collider. A sample of BB-bar pairs are tagged by reconstructing one B meson decaying semileptonically. We detect the B- -> tau- nutau-bar candidate in the recoil. We obtain a signal with a significance of 3.8 standard deviations including systematics, and measure the branching fraction to be B(B- -> tau- nutau-bar) = 1.65+0.38-0.37(stat)+0.35-0.37(syst))*10-4. This result confirms the evidence for B- -> tau- nutau-bar obtained in the previous Belle measurement with a hadronic B tagging method. The B meson decay constant fB and constraint on charged Higgs are obtained using the measured branching fraction.