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arXiv · 1011.3917

Studies of tau- -> eta.K-.nu and tau- -> eta.pi-.nu at BaBar and a search for a second-class current

The BaBar Collaboration·P. del Amo Sanchez
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Abstract

We report on analyses of tau lepton decays $τ^- \to ηK^- ν_τ$ and $τ^- \to ηπ^- ν_τ$, with $η\to π^+ π^- π^0$, using 470 fb$^{-1}$ of data from the Babar experiment at PEP-II, collected at center-of-mass energies at and near the $Υ(4S)$ resonance. We measure the branching fraction for the $τ^- \to ηK^- ν_τ$ decay mode, $\Br(τ^- \to ηK^- ν_τ) = (1.42\pm0.11\text{(stat)}\pm0.07\text{(syst)})\times10^{-4}$, and report a 95% confidence level upper limit for the second-class current process $τ^- \to ηπ^- ν_τ$, $\Br(τ^- \to ηπ^- ν_τ) < 9.9\times10^{-5}$.

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The BaBar Collaboration, P. del Amo Sanchez. 2010-11-17. Studies of tau- -> eta.K-.nu and tau- -> eta.pi-.nu at BaBar and a search for a second-class current. https://doi.org/10.1103/physrevd.83.032002

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