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arXiv · 0706.4429

Observation of B^0 \to D^{*-} \tau^+ \nu_{\tau} decay at Belle

A. Matyja·M. Rozanska
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Abstract

We report an observation of the decay $B^0\to D^{*-} \tau^+ \nu_{\tau}$ in a data sample containing $535\times10^6$ $B\bar{B}$ pairs collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We find a signal with a significance of 5.2 standard deviations and measure the branching fraction $\mathcal{B}(B^0\to D^{*-} \tau ^+ \nu_{\tau})=(2.02 ^{+0.40}_{-0.37} (stat) \pm 0.37 (syst)) % $. This is the first observation of an exclusive $B$ decay with a $b \to c \tau \nu_{\tau}$ transition.

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A. Matyja, M. Rozanska. 2007-06-29. Observation of B^0 \to D^{*-} \tau^+ \nu_{\tau} decay at Belle. https://doi.org/10.1103/physrevlett.99.191807

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