Search for the $\Lambda_{b}^{0} \rightarrow \Lambda \eta^{\prime}$ decay at LHCb

A search is performed for the as yet unobserved baryonic $\Lambda_{b}^{0} \rightarrow \Lambda \eta^{\prime}$ decay with a total integrated luminosity of 2 fb$^{-1}$ of 8 TeV data recorded by the LHCb experiment in 2012. The $B^{0} \rightarrow K_{\rm S}^{0} \eta^{\prime}$ decay is used as a control channel, and the relative branching fraction of these two decays is measured. Using a multivariate analysis, 200 $B^{0}$ signal events are observed. No significant $\Lambda_{b}^{0}$ signal is observed in the data, and an upper limit is placed on the branching fraction, $\mathcal{B}(\Lambda_{b}^{0} \rightarrow \Lambda \eta^{\prime}) <6.3\times10^{-6}$ at the 90% confidence level.