# Publications by Neville Harnew

## Observation of the suppressed decay Λb0 → pπ−μ+μ−

Journal of High Energy Physics IOP Publishing 2017 (2017) 029-

The suppressed decay Λb0 → pπ−μ+μ−, excluding the J/ψ and ψ(2S) → μ+μ− 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 fb−1 collected with the LHCb experiment. The Λb0 → pπ−μ+μ− branching fraction is measured relative to the Λb0 → J/ψ(→μ+μ−)pπ− branching fraction giving $\frac{\mathrm{\mathcal{B}}\left({\Lambda}_b^0\to p{\pi}^{-}{\mu}^{+}{\mu}^{-}\right)}{\mathrm{\mathcal{B}}\left({\Lambda}_b^0\to \mathrm{J}/\psi \left(\to {\mu}^{+}{\mu}^{-}\right)p{\pi}^{-}\right)}=0.044\pm 0.012\pm 0.007,$ where the first uncertainty is statistical and the second is systematic. This is the first observation of a b → d transition in a baryonic decay.