Search for $B^{+}\to e^{+}\nu$ and $B^{+}\to {\mu }^{+}\nu$ decays using hadronic tagging

Abstract

We present a search for the rare leptonic decays $B^{+}\to e^{+}{\nu }_e$ and $B^{+}\to {\mu }^{+}{\nu }_{\mu }$, using the full ${\rm Y}(4S)$ data sample of $772\times 10^6$ $B\bar{B}$ pairs collected with the Belle detector at the $\text{KEKB}$ asymmetric-energy $e^{+}{e}^{-}$ collider. One of the $B$ mesons from the ${\rm Y}(4S)\to B\bar{B}$ decay is fully reconstructed in a hadronic mode, while the recoiling side is analyzed for the signal decay. We find no evidence of a signal in any of the decay modes. Upper limits of the corresponding branching fractions are determined as $\mathcal{B}(B^{+}\to e^{+}{\nu }_e)<3.5\times 10^{-6}$ and $\mathcal{B}(B^{+}\to {\mu }^{+}{\nu }_{\mu })<2.7\times 10^{-6}$ at 90$\%$ confidence level.

13 pages, 7 figures, Submitted to PRD

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Cited by in corpus (1)

• Flavor Physics and CP Violation