A measurement of the $CP$ asymmetry difference in ${\Lambda }_c^{+}\to p{K}^{-}{K}^{+}$ and $p{\pi }^{-}{\pi }^{+}$ decays

The difference between the $CP$ asymmetries in the decays $\varLambda_{c}^{+} \to pK^{-}K^{+}$and$\varLambda_{c}^{+} \to p\pi^{-}\pi^{+}$ is presented. Proton-proton collision data taken at centre-of-mass energies of $7$ and $8\mathrm{T}\mathrm{e}\mathrm{V}$ collected by the LHCb detector in 2011 and 2012 are used, corresponding to an integrated luminosity of $3{\mathrm{f}\mathrm{b}}^{-1}$. The ${\Lambda }_c^{+}$ candidates are reconstructed as part of the ${\Lambda }_b^0\to {\Lambda }_c^{+}{\mu }^{-}X$ decay chain. In order to maximize the cancellation of production and detection asymmetries in the difference, the final-state kinematic distributions of the two samples are aligned by applying phase-space-dependent weights to the $\varLambda_{c}^{+} \to p\pi^{-}\pi^{+}$sample\mathrm{.}Thisaltersthedefinitionoftheintegrated$CP$asymmetryto$A_{CP}^{$\text{wgt}$}(p\pi^{-}\pi^{+})$. Both samples are corrected for reconstruction and selection efficiencies across the five-dimensional ${\Lambda }_c^{+}$ decay phase space. The difference in $CP$ asymmetries is found to be \begin{align*} \Delta{A^{$\text{wgt}$}{CP}} &= A{CP}(pK^{-}K^{+}) - A_{CP}^{$\text{wgt}$}(p\pi^{-}\pi^{+})\ &= (0.30 \pm 0.91 \pm 0.61),%, \end{align*} where the first uncertainty is statistical and the second is systematic.