Observation of the suppressed decay $\hat{I}{›}_b^0\to p\ddot{I}{€}^{-}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$

Abstract

The suppressed decay $\hat{I}{›}_b^0\to p\ddot{I}{€}^{-}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$, excluding the $J/\ddot{I}ˆ$ and $\ddot{I}ˆ(2S)\to \hat{I}{¼}^{+}\hat{I}{¼}^{-}$ resonances, is observed for the first time with a significance of 5.5 standard deviations. The analysis is performed with proton-proton collision data corresponding to an integrated luminosity of $3{\mathrm{fb}}^{-1}$ collected with the LHCb experiment. The $\hat{I}{›}_b^0\to p\ddot{I}{€}^{-}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ branching fraction is measured relative to the $\hat{I}{›}_b^0\to J/\ddot{I}ˆ(\to \hat{I}{¼}^{+}\hat{I}{¼}^{-})p\ddot{I}{€}^{-}$ branching fraction giving \begin{align} \nonumber \frac{\mathcal{B}(Λ^{0}_{b}\rightarrow pπ^{-}μ^{+}μ^{-})}{\mathcal{B}({Λ^{0}_{b}\rightarrow J/ψ(\rightarrow μ^{+}μ^{-})pπ^{-}})} &= 0.044\pm0.012\pm0.007, \end{align} where the first uncertainty is statistical and the second is systematic. This is the first observation of a $b\to d$ transition in a baryonic decay.

14 pages, 3 figures. All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-049.html