CMS-PAS-BPH-22-002

CMS-PAS-BPH-22-002
Observation of the $\Lambda^{0}_{\mathrm{b}} \to \mathrm{J}/{\psi}\,\Xi^{-}\,\mathrm{K}^{+}$ decay
CMS Collaboration
21 May 2023

Abstract: Using pp collision data corresponding to an integrated luminosity of about 140 fb $^{-1}$ collected by the CMS experiment at $\sqrt{s}=$ 13 TeV in 2016--2018, the $\Lambda^{0}_{\mathrm{b}} \to \mathrm{J}/{\psi}\,\Xi^{-}\,\mathrm{K}^{+}$ decay is observed for the first time with a significance exceeding 5 standard deviations. The relative branching fraction, with respect to the $\Lambda^{0}_{\mathrm{b}} \to \psi(\mathrm{2S})\,\Lambda$ decay, is measured to be $\mathcal{B}(\Lambda^{0}_{\mathrm{b}} \to \mathrm{J}/{\psi}\,\Xi^{-}\,\mathrm{K}^{+})/\mathcal{B}(\Lambda^{0}_{\mathrm{b}} \to \psi(\mathrm{2S})\,\Lambda) =$ [ 2.5 $\pm$ 0.8 $\pm$ 0.9 ]%, where the first uncertainty is statistical and the second one is systematic.
Links: CDS record (PDF) ; CADI line (restricted) ; These preliminary results are superseded in this paper, Submitted to EPJC. The superseded preliminary plots can be found here.

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