CMS-PAS-BPH-18-005

CMS-PAS-BPH-18-005
Study of the $\mathrm{B}^{+}\rightarrow \mathrm{J}/\psi \bar{\Lambda} \mathrm{p}$ decay in proton-proton collisions at $\sqrt{s}=$ 8 TeV
CMS Collaboration
March 2019

Abstract: A study of the $\mathrm{B}^{+} \rightarrow \mathrm{J}/\psi \bar{\Lambda} \mathrm{p}$ decay is reported, using proton-proton collision data collected at $\sqrt{s}=$ 8 TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 19.6 fb $^{-1}$ . The ratio of branching fractions ${{\cal B}(\mathrm{B}^{+} \rightarrow \mathrm{J}/\psi \bar{\Lambda} \mathrm{p})}/{{\cal B}(\mathrm{B}^{+} \rightarrow \mathrm{J}/\psi \mathrm{K}^{*+})}$ is measured to be 1.054 $\pm$ 0.057 (stat) $\pm$ 0.028 (syst) $\pm$ 0.011 ( ${\cal B}$ )%, where the first uncertainty is statistical, the second is systematic, and the third reflects the uncertainties in the world-average branching fractions. The invariant mass distributions of $\mathrm{J}/\psi \bar{\Lambda}$ , $\mathrm{J}/\psi \mathrm{p}$ , and $\bar{\Lambda} \mathrm{p}$ systems produced in the $\mathrm{B}^{+} \rightarrow \mathrm{J}/\psi \bar{\Lambda} \mathrm{p}$ decay are investigated and found to be inconsistent with the pure phase space hypothesis. The analysis is extended by using a model-independent angular amplitude analysis, which shows that the inclusion of contributions from excited kaons in the $\bar{\Lambda} \mathrm{p}$ system does improve the description of the observed invariant mass distributions.
Links: CDS record (PDF) ; inSPIRE record ; HepData record ; CADI line (restricted) ; These preliminary results are superseded in this paper, JHEP 12 (2019) 100. The superseded preliminary plots can be found here.

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