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

Abstract

The difference between the $CP$ asymmetries in the decays ${\Lambda }_c^{+}\to p{K}^{-}{K}^{+}$ and ${\Lambda }_c^{+}\to p{\pi }^{-}{\pi }^{+}$ is presented. Proton-proton collision data taken at centre-of-mass energies of $7$ and $8\mathrm{TeV}$ collected by the LHCb detector in 2011 and 2012 are used, corresponding to an integrated luminosity of $3{\mathrm{fb}}^{-1}$. 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 ${\Lambda }_c^{+}\to p{\pi }^{-}{\pi }^{+}$ sample. This alters the definition of the integrated $CP$ asymmetry to $A_{CP}^{\text{wgt}}(p{\pi }^{-}{\pi }^{+})$. 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*} Δ{A^{\text{wgt}}_{CP}} &= A_{CP}(pK^{-}K^{+}) - A_{CP}^{\text{wgt}}(pπ^{-}π^{+})\\ &= (0.30 \pm 0.91 \pm 0.61)\,\%, \end{align*} where the first uncertainty is statistical and the second is systematic.

arXiv commentAll figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2017-044.html

References in corpus (10)

• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• A Brief Introduction to PYTHIA 8.1
• LHCb Detector Performance
• PHOTOS Monte Carlo: a precision tool for QED corrections in Z and W decays
• sPlot: a statistical tool to unfold data distributions
• Standard Model CP-violation and Baryon asymmetry
• Efficient, reliable and fast high-level triggering using a bonsai boosted decision tree
• Measurement of matter-antimatter differences in beauty baryon decays
• Reweighting with Boosted Decision Trees

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