We present the results of a search for the $b\to d{\ell }^{+}{\ell }^{-}$ flavor-changing neutral-current rare decays $B^{+,0}\to (\eta ,\omega ,{\pi }^{+,0},{\rho }^{+,0})e^{+}{e}^{-}$ and $B^{+,0}\to (\eta ,\omega ,{\pi }^0,{\rho }^{+}){\mu }^{+}{\mu }^{-}$ using a $711{\mathrm{fb}}^{-1}$ data sample that contains $772\times {10}^{6}B\overline{B}$ events. The data were collected at the $\mathrm{\Upsilon }(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. We find no evidence for signal and set upper limits on branching fractions at the 90% confidence level in the range $(3.8–47)\times {10}^{-8}$ depending on the decay channel. The obtained limits are the world’s best results. This is the first search for the channels $B^{+,0}\to (\omega ,{\rho }^{+,0})e^{+}{e}^{-}$ and $B^{+,0}\to (\omega ,{\rho }^{+}){\mu }^{+}{\mu }^{-}$.

中文翻译：

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在 Belle 中寻找罕见的 b→dℓ+ℓ− 转变


我们展示了搜索结果 $b\to d{\ell }^{+}{\ell }^{-}$ 改变风味的中性电流罕见衰变 $B^{+,0}\to (\eta ,\omega ,{\pi }^{+,0},{\rho }^{+,0})e^{+}{e}^{-}$ 和 $B^{+,0}\to (\eta ,\omega ,{\pi }^0,{\rho }^{+}){\mu }^{+}{\mu }^{-}$ 使用 $711{\mathrm{fb}}^{-1}$ 数据样本包含 $772\times {10}^{6}B\overline{B}$ 事件。数据收集于 $\mathrm{\Upsilon }(4S)$ 与 Belle 探测器在 KEKB 不对称能量处共振 $e^{+}{e}^{-}$ 对撞机。我们没有发现信号证据，并在该范围的 90% 置信水平下设定了分支分数的上限 $(3.8–47)\times {10}^{-8}$ 取决于衰减通道。所获得的极限是世界上最好的结果。这是第一次搜索频道 $B^{+,0}\to (\omega ,{\rho }^{+,0})e^{+}{e}^{-}$ 和 $B^{+,0}\to (\omega ,{\rho }^{+}){\mu }^{+}{\mu }^{-}$ 。